Electrical Installation
This article is all about the non engineering side of electrical installations. Its purpose is to explain some of the techniques that are used to when installing electrical equipment and wiring in typical domestic situations.
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Cabling
Wall chasing
See the wall chaser article for more detail on the options for cutting cable chases in plaster and masonry.
Getting past coving and skirtings
It is all well and good chasing a wall with your trusty SDS drill or wall chaser, but what happens when you reach some architectural feature that you don't want to go hacking through, like a deep skirting board or ornate plaster cornice or moulding?
- Long drill bit: A very long drill bit (we are talking a minimum of 400mm here to get behind small items like picture or dado rails, or more realistically a stonking great 1m long bit bit for skirtings and coving!) can be a handy way to continue a chase behind the feature you are trying to avoid. Ideally one would need to drill straight up or down through the plaster to achieve this. This is usually impossible since you can't get the drill in the right place, or at the right angle since the wall is in the way. With small obstructions (dado etc) this may not matter, drilling down behind it at a slight angle will still be ok. For a longer vertical chase, the longer bit will be required. The trick here is to apply some sideways force to the bit as you drill. It should be possible to bend the drill such that its tip *is* parallel to the wall, while keeping the drill body and you hands at the slight angle required due to the obstruction of the wall.
- Cranked gouging chisel: specially made SDS gouges can also work well for getting behind smaller items.
- Using the other side of the wall: As simple as it sounds, in some cases the solution to avoiding difficult chases, might be to simply use the other side of the wall. This can be ideal for a cable chase on a tiled wall in a bathroom. It can also often save time where adjacent rooms have light switches "back to back" on the dividing wall - only one chase is required for the pair. Note One will need to take care that cable routes are within the prescribed zones expected - even if this means installing an extra accessory to mark the position.
Under floors
Lifting floors
- Traditional methods
- Fein Multimater / Bosch Multitool
- Broken jigsaw blade
- Plunge cut on circular saw
- Routerbout jig
Entry via a ceiling
The lateral thinkers way to get under a "difficult" upstairs floor. In many cases some new plasterboard and a bit of patching is a much quicker solution that lifting an engineered wood floor and underlay, or clearing a particularly cluttered room.
Over Ceilings
In Walls
Pull wires / cords / tapes
Push rods and sticks
Essential general tools
Much of the mechanical aspects of wiring have little to do with the things that one traditionally associates with the work of an electrician, and are really nothing more than general building and carpentry tasks.
| Type | Description |
|---|---|
| SDS Drill (3 function) | The ability to not only drill holes, but also quickly and neatly chisel out holes for socket boxes, and neat wall chases make the SDS drill a wonderful time saver. |
| Cordless drill / driver | In general cordless tools are very handy to have for electrical work since you will often be working in areas without power. Making holes, and fixing things in place probably come right near the top of list of tasks faced by anyone undertaking electrical work. A medium size (say 14.4V or better) combi drill is ideal for this sort of work. Having the hammer facility can make drilling holes into masonry for wall plugs far simpler. |
Essential electrical tools
| Type | Description |
|---|---|
| Insulated screwdrivers (VDE) | VDE tools are insulated and tested to to a high standard. This ensures that should the metal part of the tool make contact with live metalwork, no harm will come to the person holding the other end. These are absolutely essential when working on electrical installations. Not just for the rare occasions where live working is required, but the far more typical cases where one is working in close proximity to live circuits, or even on circuits that really ought to be dead, but are not!
All things said and done, you can make do some ordinary screwdrivers for jobs not involving work on electrical fittings etc, and you may choose to buy a limited set of VDE insulated drivers: a medium phillips (typical for MCB terminals) and a small and medium flat blade for other terminals. |
| Side Cutters | VDE insulated side cutters are essential (one day, you *will* pick the wrong cable to cut). Side cutters are used for cutting cables and wire to length, and they are also often invaluable for stripping cables of their outer insulation. Some cutters also include specific facilities for wire stripping, [eg]. |
| Wire Strippers | Good wire strippers make life very much simpler (while it is true that someone proficient with side cutters can often strip a wire quite satisfactorily with them as well, there is far more scope for bruised knuckles, damaged conductors, and tatty looking wire ends without them). The style of wire cutter is much a matter of personal preference. Side strippers are quick and easy to use - especially one smaller wires. The end action ones may be better for tough insulation found on the thicker and also special purpose wires. Some people also like to have an automatic wire stripper. These can make repeated stripping operations very much quicker. |
| Combination pliers | regular square nosed medium set are useful for holding, bending, and twisting wires, tightening locknuts etc. In fact anywhere you need extra gripping power. |
| Long nose pliers | A good pair of long nose pliers are the ideal tool for fishing wires out of awkward corners, and holding tricky wires in place as you tighten terminal screws. Note however that even with VDE insulated ones, care must be taken, since they have a large expanse of exposed metalwork that could easily short against live parts or earthed casework. |
Ratchet action cable crimper |
Essential for making sound wire joints which will later become inaccessible, or where space is too restrictive to allow terminal (aka "choccie blocks") to be used. See the Cable crimping article for full details of how to use these.
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Essential test gear
| Type | Description |
|---|---|
| Multimeter | |
| Volt stick | |
| Socket Tester |
Further test gear
For anything other than basic alterations and additions to existing circuits, some more sophisticated test equipment is really required. This items can be bought as separate units or as an integrated tester that combines all the functions.
| Type | Description |
|---|---|
| Insulation resistance tester ("megger") | |
| Earth loop impedance tester | |
| RCD Tester |
Good workmanship
Mechanical protection
- Capping
- Conduit
- Grommets
- Strain relief sleeves
- Glands
- Minimum bend radii
Support
- Clips
- Trunking
Making good
Once you have installed and tested all your new wiring, there is the rather more mundane task of filling all the wholes, and reinstating the fabric of the building before you lose too many household pets or children into floor voids or incur the wrath of the style police!