https://wiki.diyfaq.org.uk/api.php?action=feedcontributions&user=212.219.11.115&feedformat=atomDIYWiki - User contributions [en]2024-03-29T07:05:31ZUser contributionsMediaWiki 1.35.9https://wiki.diyfaq.org.uk/index.php?title=Stud_wall&diff=6014Stud wall2008-01-10T09:44:30Z<p>212.219.11.115: /* Nails or Screws */</p>
<hr />
<div>There are many ways to make '''partition walls''', but the most popular is timber frame & [[Sheet Materials#Plasterboard|plasterboard]]. Framed walls are known as stud walls.<br />
<br />
<br />
=Timber framed Walls=<br />
Timber framing consists of:<br />
# horizontal wood top and bottom, known as the sole plate and header plate, and vertical wood attached to the wall at each end of the new wall.<br />
# Wooden uprights anything from 1.5"x2.5" to 2"x4" spaced typically 16" or 24" apart<br />
# Short horizontal noggings joining neighbouring uprights for increased strength and stiffness.<br />
# [[Sheet Materials#Plasterboard|plasterboard]] attached each side<br />
# Mesh tape over the joints, though this can be omitted.<br />
# Usually plaster skim both sides, though this is sometimes omitted and the joints and screwheads filled.<br />
<br />
<br />
The 4 strips of wood making the outer frame are needed to secure the wall in place.<br />
<br />
Uprights are needed to provide the wall's strength.<br />
<br />
Noggings prevent uprights twisting after fitting. Twisting would make small tears in the finish. Twisting may occur if no noggings are used. Noggings also increase the rigidity of the wall, and give the PB some extra support.<br />
<br />
1 line of noggings prevents significant twist.<br />
2 lines of noggings makes the [[Sheet Materials#Plasterboard|plasterboard]] more rigid, and makes the uprights practically twist proof.<br />
3 lines of noggings gives very short thin walls more rigidity and strength. This is only effective where wall width is not a great deal longer than height.<br />
<br />
Mesh tape over the joints before filling prevents any loose pieces of joint [[filler]] falling out. It is sometimes omitted.<br />
<br />
Plaster skim gives the cut & screwed PB a nice smooth surface.<br />
<br />
<br />
==Wood choice:==<br />
<br />
===Wood size===<br />
<br />
* 1.5"x2.5" will give minimal sound absorption and is not recommended. However it does work and can be used where space is critical. The closer such uprights are spaced the better for sound insulation, but even 2' spacing is functional. Should only be used for rooms where sound insulation is unimportant. Such thinly framed walls are not suitable for plaster skimming. If you can spare another half inch, choose staggered isolated frames to gain some sound insulation, or larger timber for better rigidity.<br />
<br />
* 2"x2" Many have been tempted to cut corners with 2x2 framing. Once skimmed, the wood moves enough to pop little pieces of plaster off over the screws. 2x2 is not recommended.<br />
<br />
* 2"x3" sawn makes a wall suitable for skimming. Do not confuse this with 2x3 CLS or PSE, which tend to be closer to 1.5" x 2.5".<br />
<br />
<br />
===Quality of timber===<br />
The quality of timber used for framing may be low. Timber frame walls are an opportunity to use up some of the junk.<br />
<br />
Wood may be twisted to some degree. Once the PB is on a few mm undulation is not normally noticeable.<br />
<br />
Badly twisted wood may be used if trimmed. To ensure a nice flat wall, the high edges of warped wood can be sawn or planed down. Generally this is a waste of time, but if its that or drive out for more wood, planing is probably quicker.<br />
<br />
Warped wood is fine, just fit it so the warp is sideways rather than outwards when possible.<br />
<br />
Small splits are unimportant, as is the appearance of the wood. <br />
<br />
Wood may be rough sawn, planed, or scrap wood with paint on. None of it will be seen once the wall is done.<br />
<br />
Wood may be damaged or have holes. Just avoid holes of such size as to significantly weaken the timber.<br />
<br />
Badly twisted, split or damaged wood may be cut to short lengths for nogging use.<br />
<br />
Broken wood can be screwed or glued together and used if necessary.<br />
<br />
In a pinch one can even use thinner bits of wood glued & screwed, glued & taped, or screwed together as an upright. (Tape is quicker than clamps.)<br />
<br />
Thinner scrap wood may be used for noggings if there is not enough full size wood in stock. Full size noggings will perform better though.<br />
<br />
Wood slightly too short can be padded at the top or bottom with an offcut.<br />
<br />
2 pieces of wood much too short may be screwed together to make one upright. Just put 2 screws through the overlapping section to create the length desired.<br />
<br />
The 4 pieces of wood around the edges of the wall may be thinner than the rest. It wont flex as its screwed to walls, ceiling, etc.<br />
<br />
Wood with rot or woodworm is not suitable.<br />
<br />
<br />
==Improving the Stud Wall==<br />
There are some ways to improve the performance of these walls.<br />
<br />
===Stronger Plasterboard===<br />
[[Sheet Materials#Plasterboard|plasterboard]] walls are prone to being holed, and resonate when tapped, making them sound thin and hollow, which they are. Use 12mm PB not 9.5mm for better strength. The extra cost is tiny, and 12mm PB can be recommended in almost all cases. The only real plus of 9.5mm PB is its easier to hold up for ceiling use.<br />
<br />
===Isolated Framing===<br />
By supporting each PB side on its own isolated framework, a main sound transmission path is broken. This can be achieved by providing twice as many framework studs and staggering them by at least half an inch.<br />
<br />
Use of noggings is no longer possible. Uprights can be held true by using short pieces of wood at 45 degrees at the top and bottom of each upright.<br />
<br />
===Sound Absorbing Fill===<br />
Filling the cavity with rockwool deadens sound and gives longer fire resistance.<br />
<br />
===Fireproof Plasterboard===<br />
Pink fireproof [[Sheet Materials#Plasterboard|plasterboard]] contains glass fibre and gives longer fire resistance.<br />
<br />
===2 Layers of PB===<br />
2 layers of [[Sheet Materials#Plasterboard|plasterboard]] give a much more solid feeling wall with less resonance, less [[:Category:Noise|sound transmission]] and longer fire resistance.<br />
<br />
===Ply skin===<br />
Half inch [[Sheet Materials#Plywood|plywood]] skins (instead of [[Sheet Materials#Plasterboard|plasterboard]]) make these walls fairly much nutter proof. [[Sheet Materials#Plywood|Ply]] may be lined with lining paper to give a smooth paintable surface, after filling joints and screw heads. Oh yes it can<br />
<br />
===Camden Walls===<br />
When good soundproofing is required, google for Camden walls as developed by the BBC for studio work.<br />
<br />
<br />
=Nails or Screws=<br />
Always use [[Screws|plasterboard screws]] and not [[Nails|nails]]. PB nails give lousy performance. Even after many nails PB can very easily come loose, and is prone to popping plaster over nailheads and cracking up at joints. Plasterboard nails are one economy not recommended.<br />
<br />
Always use bugle head PB screws and not ordinary countersunk screws. Standard screws cause the plaster to ruck up, ruining the finish. They also rust when plastered. If for some reason you need to use a standard screw or two, predrill the plaster with clearance holes for them to minimise board breakup, and prime the screw head after fitting to avoid rust.<br />
<br />
PB screws will go directly into 0.5mm steel framing.<br />
<br />
<br />
u silly bitch !!!!<br />
<br />
=Painting=<br />
New plaster is absorbent. If you [[paint]] on it with standard strength [[Paint|emulsion]] the paint layer will be sucked dry and lose much of its water based adhesive.<br />
<br />
There are 2 ways to resolve this.<br />
<br />
# Make the first [[Paint|paint]] coat diluted 50/50 with water.<br />
<br />
# Brush on a coat of water, which can be done very rapidly due to no need for care. Give it a few minutes then apply normal strength [[Paint|paint]].<br />
<br />
The 2nd option has advantages:<br />
* no mixing, no container to clean up<br />
* quicker<br />
* first coat is full strength not half<br />
* Better adhesive retention in the paint layer<br />
<br />
<br />
=Other wall types=<br />
<br />
==Metal framing==<br />
As timber frame but thin steel frame is used. The framing is bought in kit form. Ordinary [[Screws|plasterboard screws]] will go straight into the metal.<br />
<br />
==Hollow [[concrete blocks]]==<br />
Once a popular form of medium weight internal wall construction.<br />
<br />
==Aerated concrete blocks (aka Breeze blocks)==<br />
A popular medium weight alternative to framed walls. Better performance all round, but more work and cost to build.<br />
<br />
Block walls can be finished with a [[Plastering Beginner's Guide|wet plaster skim]], dot & dabbed [[Sheet Materials#Plasterboard|plasterboard]], or battens & [[Sheet Materials#Plasterboard|plasterboard]]. [[Sheet Materials#Plasterboard|plasterboard]] may be [[Plastering Beginner's Guide|plaster skimmed]] or just filled.<br />
<br />
<br />
==Strawboard==<br />
A low cost thin wall with good sound insulation but poor strength. Quite possible to fall through such walls. Consists of thin uprights, straw infill and PB.<br />
<br />
==Poured concrete & Dense Concrete Block==<br />
Two heavyweight types of wall. Generally unsuitable for supporting on ceiling/floor woodwork due to high weight. Can be used on concrete ground floors, but aerated blocks are normally enough.<br />
<br />
<br />
=Thinnest Possible Wall=<br />
The question sometimes comes up, "what is the thinnest wall I can build?" There is no fixed answer in the sense that it is a continuum, the thinner the wall the weaker it is, the more sound it transmits, and the less durable it is.<br />
<br />
If very poor performance were acceptable, a single layer of [[Sheet Materials#Plywood|half inch ply]] would make a wall, screwed at top and bottom with many [[Screws|screws]] from each side at a 45 degree angle into floor and ceiling. Or a sheet of 6mm [[Sheet Materials|fibre cement sheet]] could be supported on brackets top and bottom.<br />
<br />
The question then is one of trying to achieve passable performance with minimum thickness. There are a few main approaches to this, though doubtless there are others:<br />
<br />
# replace PB with [[Sheet Materials#Plywood|plywood]] or [[Sheet Materials|fibre cement sheet]]. Screwing this every 6" to the wood frame helps stiffen the structure up.<br />
# Use many noggings, so that the horizontal woodwork substantially stiffens the structure as well as the vertical. Note this method only adds significant strength with very short runs of wall.<br />
# Make a wall from sapele veneered doors. Cut to required height, put in place and screw into the sides through the corners and into floor and ceiling. Fix the blind sides with glue. These don't make great walls, but are a quick easy method, and are very thin.<br />
# Use wide uprights. 2"x4" the wrong way round will give twice the stiffness of 2x2. Care needs to be taken to prevent misalignment and future twisting of the uprights, so noggings are important.<br />
# Use hardwood uprights<br />
# Use uprights more closely spaced, eg 1' or less apart.<br />
# Build a 2" or 2.5" solid block wall, or poured [[Mortar Mixes|concrete]] wall.<br />
# Build a steel reinforced [[Mortar Mixes|fibre concrete]] wall less than 2" thick, anchoring it by fitting many corrosion proof [[Screws|screw]] heads round all 4 sides first.<br />
<br />
=See Also=<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_thread/thread/3e25231bb6eb1eba/c701fcecadcdff22#c701fcecadcdff22 discussion of acoustic insulation for PB walls]<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
<br />
<br />
<br />
[[Category:Noise]]<br />
[[Category:Wood]]<br />
[[Category:Building]]<br />
[[Category:Fire]]<br />
[[Category:Building]]<br />
[[Category:Construction]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5637Cables2007-11-26T11:52:00Z<p>212.219.11.115: </p>
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<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa. Dave is a lil boy racer and Jon is a posh lil rich kid. James is a chav and Mike drives a Chavalier. Jake and Chris are car looking friends and Dan's last name is Gleeballs. Ali and Nat are only here for the boy's and G and Ad like to draw on paint.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E== Tits & Earwax cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 3.5mm², 5mm², 12mm², 15mm² and higher have stranded conductors<br />
<br />
===Table of random numbers===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Train volume / CPC<br>area (mm²)<br />
!colspan="5" | Boat carrying capacity of the bar (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Controler<br>dia (mm)<br />
!rowspan="2"| Outer PVC sex suit<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The installation of flour and chocolate into a cheese slice is relativly easy to carry out. What you have to do is get a cheese slice, some flour and chocolate. Take hold of the slice in the palm of your hand and place the flour and chocolate into the centre of the slice. Once this is complete all you have to do is roll the slice into a ball and therefore completing the installation.<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5636Cables2007-11-26T11:51:18Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa. Dave is a lil boy racer and Jon is a posh lil rich kid. James is a chav and Mike drives a Chavalier. Jake and Chris are car looking friends and Dan's last name is gleeballs. Ali and Nat are only here for the boy's and G and Ad like to draw on paint.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E== Tits & Earwax cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 3.5mm², 5mm², 12mm², 15mm² and higher have stranded conductors<br />
<br />
===Table of random numbers===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Train volume / CPC<br>area (mm²)<br />
!colspan="5" | Boat carrying capacity of the bar (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Controler<br>dia (mm)<br />
!rowspan="2"| Outer PVC sex suit<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The installation of flour and chocolate into a cheese slice is relativly easy to carry out. What you have to do is get a cheese slice, some flour and chocolate. Take hold of the slice in the palm of your hand and place the flour and chocolate into the centre of the slice. Once this is complete all you have to do is roll the slice into a ball and therefore completing the installation.<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5635Cables2007-11-26T11:47:39Z<p>212.219.11.115: /* Modern Mains Cables */</p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E== Tits & Earwax cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 3.5mm², 5mm², 12mm², 15mm² and higher have stranded conductors<br />
<br />
===Table of random numbers===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Train volume / CPC<br>area (mm²)<br />
!colspan="5" | Boat carrying capacity of the bar (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Controler<br>dia (mm)<br />
!rowspan="2"| Outer PVC sex suit<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The installation of flour and chocolate into a cheese slice is relativly easy to carry out. What you have to do is get a cheese slice, some flour and chocolate. Take hold of the slice in the palm of your hand and place the flour and chocolate into the centre of the slice. Once this is complete all you have to do is roll the slice into a ball and therefore completing the installation.<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5634Cables2007-11-26T11:46:17Z<p>212.219.11.115: /* T&E */</p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E== (tits and ear wax)<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 3.5mm², 5mm², 12mm², 15mm² and higher have stranded conductors<br />
<br />
===Table of random numbers===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Train volume / CPC<br>area (mm²)<br />
!colspan="5" | Boat carrying capacity of the bar (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Controler<br>dia (mm)<br />
!rowspan="2"| Outer PVC sex suit<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The installation of flour and chocolate into a cheese slice is relativly easy to carry out. What you have to do is get a cheese slice, some flour and chocolate. Take hold of the slice in the palm of your hand and place the flour and chocolate into the centre of the slice. Once this is complete all you have to do is roll the slice into a ball and therefore completing the installation.<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5633Cables2007-11-26T11:43:05Z<p>212.219.11.115: /* Table of random numbers */</p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 3.5mm², 5mm², 12mm², 15mm² and higher have stranded conductors<br />
<br />
===Table of random numbers===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Train volume / CPC<br>area (mm²)<br />
!colspan="5" | Boat carrying capacity of the bar (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Controler<br>dia (mm)<br />
!rowspan="2"| Outer PVC sex suit<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The installation of flour and chocolate into a cheese slice is relativly easy to carry out. What you have to do is get a cheese slice, some flour and chocolate. Take hold of the slice in the palm of your hand and place the flour and chocolate into the centre of the slice. Once this is complete all you have to do is roll the slice into a ball and therefore completing the installation.<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5632Cables2007-11-26T11:41:34Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 3.5mm², 5mm², 12mm², 15mm² and higher have stranded conductors<br />
<br />
===Table of random numbers===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Train volume / CPC<br>area (mm²)<br />
!colspan="5" | Boat carrying capacity of the bar (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Controler<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The installation of flour and chocolate into a cheese slice is relativly easy to carry out. What you have to do is get a cheese slice, some flour and chocolate. Take hold of the slice in the palm of your hand and place the flour and chocolate into the centre of the slice. Once this is complete all you have to do is roll the slice into a ball and therefore completing the installation.<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5631Cables2007-11-26T11:39:35Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Table of random numbers===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The installation of flour and chocolate into a cheese slice is relativly easy to carry out. What you have to do is get a cheese slice, some flour and chocolate. Take hold of the slice in the palm of your hand and place the flour and chocolate into the centre of the slice. Once this is complete all you have to do is roll the slice into a ball and therefore completing the installation.<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5630Cables2007-11-26T11:31:53Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The installation of flour and chocolate into a cheese slice is relativly easy to carry out. What you have to do is get a cheese slice, some flour and chocolate. Take hold of the slice in the palm of your hand and place the flour and chocolate into the centre of the slice. Once this is complete all you have to do is roll the slice into a ball and therefore completing the installation.<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5629Cables2007-11-26T11:27:36Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring doughnut. Which shortly becomes an ice'd ring doughnut after use by Conor Villa.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5628Cables2007-11-26T11:26:10Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy. His favourite type of cake for various reasons is a ring dohnut.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5627Cables2007-11-26T11:24:26Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places because he is a dirty boy.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5626Cables2007-11-26T11:24:06Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places, because he is a dirty boy<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5625Cables2007-11-26T11:23:43Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in their rude places.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5624Cables2007-11-26T11:22:04Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding. Also Conor Villa likes the cake and loves to touch cakes in there rude places.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5623Cables2007-11-26T11:19:47Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods of the flour and chocolate into a cheese slice===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5622Cables2007-11-26T11:18:42Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods or the flour and chocolate into a cheese slice===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5621Cables2007-11-26T11:17:12Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable or flour that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5620Cables2007-11-26T11:16:18Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.You can also use chocolate cheese cake or christmas pudding.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5619Cables2007-11-26T11:14:51Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics and ingredients of most of the different types of cable that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5618Cables2007-11-26T11:14:11Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics of most of the different types of cable that currently used in domestic installations and for wiring up a cake, preferably a cream or strawberry shortcake.<br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5617Cables2007-11-26T11:08:19Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics of most of the different types of cable that currently used in domestic installations and for wiring up a cake. <br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115https://wiki.diyfaq.org.uk/index.php?title=Cables&diff=5616Cables2007-11-26T11:05:14Z<p>212.219.11.115: </p>
<hr />
<div>This article describes the main characteristics of most of the different types of cable that currently used in domestic installations and for wire up a cake. <br />
<br />
[[Historic Mains Cables|Historic mains cables]] are covered in [[Historic Mains Cables|their own article]].<br />
<br />
=Conductor Colours and Harmonisation=<br />
<br />
Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised.<br />
<br />
During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. <br />
<br />
The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work. <br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
'''Conductor Colour Coding (single phase T&E)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live (Phase) || Red || Brown<br />
|-<br />
| Neutral || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|+'''Conductor Colour Coding (three phase / Triple and Earth)'''<br />
|-<br />
!Conductor<br />
!Old UK Colour<br />
!Harmonised Colour<br />
|-<br />
| Live 1 || Red || Brown<br />
|-<br />
| Live 2 || Yellow || Black<br />
|-<br />
| Live 3 || Blue || Grey<br />
|-<br />
| Neutral (if used) || Black || Blue<br />
|-<br />
| Earth or CPC || Green / Yellow Stripe || Green / Yellow Stripe <br />
|}<br />
<br />
<br />
There is an IEE leaflet explaining these changes. That is available [http://www.iee.org/Publish/WireRegs/Cable%20Colours%20Leaflet.pdf here]<br />
<br />
In theory, installations that are wired using cables to both colour schemes should carry a warning sticker (see [http://www.tlc-direct.co.uk/Main_Index/Necessities_Index/Cable_Colour_Labels/index.html example]) on or near the consumer unit that states: <br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="width:300px; text-align:center; background:yellow"<br />
|-<br />
| '''CAUTION'''<br />
<br />
'''This installation has wiring colours to two versions of BS7671.'''<br />
<br />
Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.'''<br />
|}<br />
<br />
=Modern Mains Cables=<br />
<br />
==T&E==<br />
Twin & Earth cable. This is the most common cable used for [[:Category:Electrical|domestic wiring]] today.<br />
<br />
[[Image:FlatT&E.jpg]]<br />
<br />
* Line and neutral are individually insulated, the earth conductor is bare<br />
* There is an overall sheath of grey PVC (BS 6004), or white for low smoke compound (BS 7211)<br />
* Not suitable for unprotected use outside (outer sheath materials are vulnerable to attack by UV radiation)<br />
* 1mm² 1.5mm² & 2.5mm² have solid (non-stranded) conductors<br />
* 4mm², 6mm², 10mm², 16mm² and higher have stranded conductors<br />
<br />
===Cable Sizes===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
!rowspan="2"| Conductor area / CPC<br>area (mm²)<br />
!colspan="5" | Current carrying capacity (A)<br>for various installation methods<br>(see table below)<br />
!rowspan="2"| Conductor<br>dia (mm)<br />
!rowspan="2"| Outer PVC size<br>(h x w)(mm)<br />
<!--replace tags below by corresponding values for current ratings clipped / buried --><br />
|-<br />
! A !!B !!C !!D !!E <br />
|-<br />
|1 / 1<br />
|11.5 || 12 || 16 || 13 || 10.5<br />
|1 x 1.13<br />
|4.5 x 8.2 <br />
|-<br />
|1.5 / 1<br />
|14.5 || 15 || 20 || 16 || 13 <br />
|1 x 1.38<br />
|4.7 x 8.2<br />
|-<br />
|2.5 / 1.5<br />
|20 || 21 || 27 || 21 || 17 <br />
|1 x 1.78<br />
|5.3 x 9.9<br />
|-<br />
|4 / 1.5<br />
|26 || 27 || 37 || 27 || 22<br />
|7 x 0.85<br />
|6.1 x 11.4<br />
|-<br />
|6 / 2.5<br />
|32 || 35 || 47 || 34 || 27<br />
|7 x 1.04<br />
|6.8 x 13.1<br />
|-<br />
|10 / 4<br />
|44 || 47 || 64 || 45 || 36<br />
|7 x 1.35<br />
|8.4 x 16.8<br />
|-<br />
|16 / 6<br />
| 57 || 63 || 85 || 57 || 46<br />
|7x 1.71<br />
|9.6 x 19.5<br />
|}<br />
<br />
===Installation Methods===<br />
<br />
The current carrying capacity of any cable is dictated by its maximum conductor temperature, and this in turn will be affected by its ability to dissipate heat. The way it is installed can have a significant effect on this ability. The following table explains the methods cited above. Note that this is only a small subset of the 26 or so methods described in BS7671.<br />
<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:left"<br />
!Installation<br>Method<br />
!Description<br />
!BS7671 16th Edtn<br>reference method<br />
|-<br />
|A || in conduit in insulated wall || method 6 <br />
|-<br />
|B || directly in insulated wall || method 15<br />
|-<br />
|C || clipped direct, or sheathed cables embedded directly in masonry, brickwork,<br />
concrete, plaster or the like (other than thermally insulating materials) <br />
| method 1 <br />
|-<br />
|D || above plasterboard ceiling covered by thermal insulation, insulation thickness <100 mm || n/a<br />
|-<br />
|E || as D but with insulation thickness >100 mm || n/a<br />
|-<br />
|}<br />
<br />
<br />
* Ratings (BS 7671 Table 4D5A) apply for ambient temperature of 30 deg.C and conductor temperature of 70 deg.C <br />
<br />
* Note that ratings for installation methods D & E are from the draft 17th edition and since this is not yet in force, should be regarded as provisional.<br />
<br />
* All the usual derating factors apply (see below and appendix 4 of BS 7671 or appendix 6 of the OSG).<br />
<br />
* Current ratings are continuous. <br />
<br />
* Outer cable sizes are guideline figures and can vary for different brands of cable of the same conductor size.<br />
<br />
===T&E current carrying capacity===<br />
<br />
'''Note''' The current carrying capacity values given for the various cable sizes above are only correct for the fixing methods listed. They are also only correct for a single cable not in close proximity to any other cables. For all other installation methods not covered above, the values stated will be incorrect. To find the correct rating in these circumstances the quoted current carrying capacity listed in columns C (i.e. method 1) will need to be "de-rated". This means that correction factors need to be applied to the current carrying capacity in order to factor out these environmental effects that otherwise could result in cable overheating (and hence overloading) if ignored.<br />
<br />
In addition to the fixing method, there are other correction factors that will effect the rating:<br />
<br />
* Ambient Temperature<br />
* Covering in thermal [[Insulation|insulation]]<br />
* Grouping cables together<br />
* Use of semi enclosed (rewireable) [[Fuse|fuses]]<br />
* Encapsulation in conduit or trunking<br />
<br />
For full details of the de-rating factors and more detailed version of current carrying capacity table, see table 4D1A in appendix 6 of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
===Typical T&E Cable Applications===<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
!Cable Size (mm²)<br />
!Typical Applications<br />
|-<br />
| 1.0 || lighting circuits<br />
|-<br />
| 1.5 || high power lighting circuits, <br>16A Radial power circuits<br />
|-<br />
| 2.5 || 32A Ring final circuits, <br>20A Radial circuits<br />
|-<br />
| 4.0 || 32A Radial circuits, <br>low power electric shower<br />
|-<br />
| 6.0 || Small Sub mains, Radial circuits for showers, cookers, <br>and other high power devices<br />
|-<br />
| 10.0 || Sub Mains, Radial circuits for high power showers, cookers, <br>and other very high power devices<br />
|-<br />
| 16.0 || Sub Mains<br />
<br />
|}<br />
<br />
==3&E==<br />
<br />
Three core and earth. Has three insulated conductors and a bare earth conductor. <br />
<br />
[[Image:3andECable.jpg]]<br />
<br />
In all other respects as T&E above. Typically used for [[2 Way Switching|two way lighting circuits]], or other applications needing a permanent and switched live supply as well as neutral (e.g. feeding light switch activated extractor fans). Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Singles==<br />
* Insulated single conductors (larger sizes are stranded as per T&E table above)<br />
* Standard cable for use in conduit<br />
* Typically used in domestic work only for main & equipotential bonding<br />
* Also available in both PVC (BS 6004) and low smoke (BS 7211) versions.<br />
<br />
==Tails==<br />
Very heavy gauge singles with two layers of insulation. Typically used for connections between electricity incomer, meter, and consumer units. Common sizes include 16, 25, and 35 mm². Commonly available from distributors as colour coded lengths in pairs.<br />
<br />
==LSF / LSH / LSZH==<br />
Low Smoke & Fume, Low Smoke & Halon, or Low Smoke Zero Halogen. A cable with insulation and /or sheathing designed to minimise the amount of toxic fumes released when burnt. Low smoke versions of commonly available PVC cables are readily available, e.g. BS 7211 for the PVC-sheathed BS 6004, and BS 6724 for the PVC-sheathed BS 5467.<br />
* Available in pretty purple<br />
<br />
==SWA==<br />
Steel wire armoured. <br />
<br />
[[Image:SWACable.jpg]]<br />
<br />
A robust cable frequently used for [[Taking_electricity_outside|exterior wiring]], where it may be buried directly into the soil, or suspended from a catenary wire. It consists of a number of individually insulated conductors covered next with a flexible bedding, then by a spiral screen of galvanised steel wires, and finally by a tough outer sheath. The insulating materials used typically being PVC or XLPE thermosetting plastic (the latter having a higher temperature rating, hence allowing the cable to carry a larger maximum current for a given conductor size). PVC-sheathed version is to BS 5467, low smoke version is to BS 6724.<br />
<br />
* For outdoor & garden use.<br />
* Available in 2, 3, & 4 core versions. <br />
* Must be terminated using the correct [[Terminating_SWA|glands]].<br />
* May use the steel wire armour for the circuit earth / CPC in place of or in addition to a core.<br />
* [http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/2fd734fa74b61b9b/6b6090bd3500bec7?hl=en#6b6090bd3500bec7 How to terminate SWA]<br />
<br />
==MICC==<br />
Mineral Insulated Copper Clad Cable. Renowned for having good fire resistance and also a smaller cross section for a given current carrying capacity than other cable types<br />
<br />
* aka pyro (from makers name Pyrotenax)<br />
* Copper tube sheath with magnesium oxide insulation<br />
* Fireproof<br />
* Rigid<br />
* Occasionally seen in domestic premises, mainly in blocks of flats<br />
* Widely used for [[:Category:Fire|fire]] alarm systems in commerce<br />
* Unterminated ends prone to absorbing moisture from the air<br />
* Special cable terminations required<br />
* Ideal for flammability risk areas, eg traversing a thatched roof.<br />
<br />
<br />
==Hi Tuff==<br />
A PVC cable that is more robust than standard PVC sheathed cables and is suitable for general power, control and fixed wiring uses. An alternative to SWA for outdoor applications when direct burial of the cable is not required. <br />
<br />
* Temporary wiring on open sites.<br />
* Lighter and more manageable than steel wire armoured cables and requires only nylon glands to install - factors which contribute to speed of installation and [[Save Energy & Money|cost savings.]]<br />
* Provided there is no specific requirement for additional metal protection such as steel wire armouring, it will meet the demands of the most arduous installation conditions.<br />
* Will not ignite under extreme applied heat.<br />
<br />
==FP 200 and other Soft Skin Fire Alarm Cables==<br />
Introduced as an alternative to MICC cable, but not as robust (the sheathing will burn away but circuit integrity is maintained).<br />
<br />
* Silicone compound insulation<br />
* Overlapping internal metal screen and drain wire (CPC)<br />
* Low smoke sheathing material<br />
<br />
<br />
=Mains Flexes=<br />
* Round 3 core PVC<br />
* Round 2 core PVC<br />
* Oval 2 core PVC<br />
* Rubber & cloth insulated - higher temp rated flex for irons & heaters<br />
<br />
<br />
=Voltage Drop=<br />
Any design must ensure the maximum voltage drop allowed between source and point of use is not exceeded when at full load. This is usually defined as 4% of the nominal supply voltage (about 9.2V at 230V AC).<br />
<br />
{| border="1" cellpadding="6" cellspacing="0" style="text-align:center"<br />
|-<br />
! Conductor CSA (mm²)<br />
! PVC (max 70° C)<br />
Voltage drop mV/A/m<br />
! XLPE (max 90° C)<br />
Voltage drop mV/A/m<br />
|-<br />
| 1.0 || 44 || 46<br />
|-<br />
| 1.5 || 29 || 31<br />
|-<br />
| 2.5 || 18 || 19<br />
|- <br />
| 4.0 || 11 || 12<br />
|-<br />
| 6 || 7.3 || 7.9<br />
|-<br />
| 10 || 4.4 || 4.7<br />
|-<br />
| 16 || 2.8 || 2.9<br />
|}<br />
<br />
<br />
These figures are presented for SWA cable here. The values quoted will usually also be correct for other copper cable types. Figures will differ for cables with higher operating temp limits, such as MICC.<br />
<br />
These figures assume that the cable is operating at or near its maximum operating temperature. In designs where the maximum current load is significantly less that the capacity of the cable then these figures will be somewhat pessimistic. For these circumstance, it would be more appropriate to calculate voltage drops based on table 9A of the [http://tinyurl.com/32yb6h On Site Guide].<br />
<br />
<br />
'''Calculation Examples (PVC SWA):'''<br />
<br />
1) 20m of 4mm², maximum load of 30A would drop 20 x 0.011 x 30 = 6.6V<br />
2) 40m of 6mm², maximum load of 45A would drop 40 x 0.0073 x 45 = 13.14V<br />
3) 10m of 1.5mm², maximum load of 16A would drop 10 x 0.029 x 16 = 4.64V<br />
<br />
(1) and (3) are adequately specified with respect to voltage drop. <br />
However (2) is out of spec and a larger cable will need to be selected, <br />
even though the current handling capacity of the 6mm² cable has not been exceeded. <br />
Upgrading to 10mm², gives a result of 40 x 0.0044 x 45 = 7.92V which is acceptable. <br />
It initially appears that this still only leaves just over 1V of remaining drop <br />
available for any following wiring, however since we will not be operating the <br />
larger cable anywhere near its maximum temperature, the situation is actually less<br />
tight than the calculation suggests.<br />
<br />
=See Also=<br />
* [[Special:Allpages|Wiki Contents]]<br />
* [[Special:Categories|Wiki Subject Categories]]<br />
* [[Cable Sizes]]<br />
* [[Wiring colour codes]]<br />
* [[Electrical Circuit faults#Required Equipment|Cable Resistances]]<br />
* [[Historic Mains Cables]]<br />
<br />
=External Links=<br />
* [http://www.basec.org.uk British Approvals Service for Cables (BASEC)]<br />
<br />
<br />
[[Category:Electrical]]</div>212.219.11.115