Understanding harmonised cable codes
An effort by CENELEC (a European standards committee) to harmonise the classification of cables had lead to a coding system that you will often see used to specify the detailed characteristics of a cable or flex (more commonly used for the latter it seems). These designations are often written in the form H05RN-F or H05BN-F etc. While they actually give you lots of technical detail about the cable in a very short code, they do take quite a bit of deciphering!
The code
The codes break down into three parts:
Part 1 of the Designation
Table 1a gives you the standards compliance and maximum nominal voltage
| Symbol | Conformance to Standards |
| H | Cable conforms with the harmonised standards |
| A | Cable conforms with a Recognised National Type, listed in a Supplement to the harmonised standards |
Table 1b Gives the voltage rating of the cable
| Symbol | Voltage Rating, Single/3Ph |
| 01 | >= 100/100V to < 300/300V |
| 03 | 300/300V |
| 05 | 300/500V |
| 07 | 450/750V |
Part 2 of the Designation
Table 2a gives you the insulating material and the designation of any non metallic sheath. Hence you need two sets of letters from this table, the first to describe the insulator used for the conductors themselves, and the second to tell you about the material used for the overall sheath.
| Symbol | Material |
| B | Ethylene-propylene rubber (Continuous operation up to 90°C) |
| G | Ethylene-vinyl-acetate |
| J | Glass-fibre braid |
| M | Mineral |
| N | Polychloroprene (or equivalent material) |
| N2 | Special polychloroprene compound for covering of welding cables according to HD 22.6 |
| N4 | Chlorosulfonated polyethylene or chlorinated polyethylene |
| N8 | Special water resistant polychloroprene compound |
| Q | Polyurethane |
| Q4 | Polyamide |
| R | Ordinary ethylene propylene rubber or equivalent synthetic elastomer for a continuous operating temperature of 60ºC |
| S | Silicone rubber |
| T | Textile braid, impregnated or not, on assembled cores |
| T6 | Textile braid, impregnated or not, on individual cores of a multi-core cable |
| V | Ordinary PVC |
| V2 | PVC compound for a continuous operating temperature of 90ºC |
| V3 | PVC compound for cables installed at low temperature |
| V4 | Cross-linked PVC |
| V5 | Special oil resistant PVC compound |
| Z | Polyolefin-based cross-linked compound having low level of emission of corrosive gases and which is suitable for use in cables which, when burned, have low emission of smoke |
| Z1 | Polyolefin-based thermoplastic compound having low level of emission of corrosive gases and which is suitable for use in cables which, when burned, have low emission of smoke |
So for example With H05RN-F, the R tells you the wires are insulated in Ordinary ethylene propylene rubber, and the N that the overall insulation is Polychloroprene
Table 2b gives a number of possible metallic coverings:
| Symbol | Sheath, concentric conductors and screens |
| C | Concentric copper conductor |
| C4 | Copper screen as braid over the assembled cores |
Table 2c for some special constructions of components of the cable:
| Symbol | Sheath, concentric conductors and screens |
| D | Strain-bearing element consisting of one or more textile components, placed at the centre of a round cable or distributed inside a flat cable |
| D5 | Central heart (non strain-bearing for lift cables only) |
| D9 | Strain-bearing element consisting of one or more metallic components, placed at the centre of a round cable or distributed inside a flat cable |
Next, you may get any of the following tacked onto the ends of codes from tables a to c above:
Table 2d Special constructions of whole cable
| Symbol | Special construction |
| No Symbol | Circular construction of cable |
| H | Flat construction of “divisible” cables and cores, either sheathed or non-sheathed |
| H2 | Flat construction of “non-divisible” cables and cores |
| H6 | Flat cable having three or more cores, according to DH 359 or EN 50214 |
| H7 | Cable having a double layer insulation applied by extrusion |
| H8 | Extensible lead |
Next an optional group for specifying the conductor material. This is only required for non copper conductors and will follow a dash.
Table 2e Conductor material
| Symbol | Conductor material |
| No Symbol | Copper |
| -A | Aluminium |
Lastly, Again these follow after a dash (the same one as that used to specify aluminium conductors above if present!)
Table 2f Conductor form
(note for cables with two forms of conductor, the specification applies to the phase conductor only)
| Symbol | Conductor form |
| -D | Flexible conductor for use in arc welding cables to HD 22Part 6 (flexibility different from Class 5 of HD 383) |
| -E | Highly flexible conductor for use in arc welding cables to HD22 Part 6 (flexibility different from Class 6 of HD 383) |
| -F | Flexible conductor of a flexible cable or cord (flexibility according to Class 5 of HD 383) |
| -H | Highly flexible conductor of a flexible cable or cord (flexibility according to Class 6 of HD 383) |
| -K | Flexible conductor of a cable for fixed installations (unless otherwise specified, flexibility according to Class 5 of HD 383) |
| -R | Rigid, round conductor, stranded |
| -U | Rigid round conductor, solid |
| -Y | Tinsel conductor (Tinsel conductors are used in flexes for small appliances were normal stranded flex would be likely to fatigue and break - its made with a conductive foil wrapped around a supporting textile or plastic core to provide the tensile strength) |
Part 3 of the Designation
Table 3 Number of cores and the nominal cross sectional area of each core.
| Symbol | Number and size of conductors |
| (number) | Number, n of cores |
| X | Times, where a green/yellow core is not included |
| G | Times, when a green/yellow core is included |
| (number) | Nominal cross-section, s, of conductor in mm²
(Note an N after the number of cores indicates the cores are identified by numbers rather than or in addition to colours) |
| Y | For a tinsel conductor where the cross-section is not specified |
Fitting all the bits together
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
| Part 1 | Part 2 | Part 3 | ||||||||
| Related standard |
Rated voltage |
Insulating material |
Metallic coverings (2) |
Non-metallic sheath (2) |
Constructional components and special constructions |
Conductor material |
Conductor forms |
Number of cores | Times | Conductor size mm² |
| Symbols according to tables | ||||||||||
| 1a | 1b | 2a | 2b | 2a | 2c and 2d | 2e | 2f | 3 | ||
| H | 01 | B | C | B | D3 | No | -D | 1 | X | Y |
| D5 | symbol: | -E | 2 | 0.5 | ||||||
| A | 03 | G | C4 | G | copper | -F | 3 | G | ||
| ----- | -H | 4 | 0.75 | |||||||
| 05 | J | J | No symbol: | -A | -K | 5 | ||||
| circular | -R | etc | 1 | |||||||
| 07 | M | construction of | -U | |||||||
| cable | -Y | 1.5 | ||||||||
| N, N4 | N,N2,N4,N8 | |||||||||
| H | 2.5 | |||||||||
| Q, Q4 | H2 | |||||||||
| H6 | 4 | |||||||||
| R | R | H7 | ||||||||
| H8 | 6 | |||||||||
| S | S | |||||||||
| 10 | ||||||||||
| T, T6 | ||||||||||
| 16 | ||||||||||
| V, V2, | V, V2, V3, | |||||||||
| V3, V4 | V4, V5 | 25 | ||||||||
| Z, Z1 | Z, Z1 | etc | ||||||||
(1) If two or more symbols listed in the same column need to be used in a given designation, they shall follow each other in their radial sequence starting from the core axis or cable axis.
(2) The symbols might change their position in the designation with respect to the construction of the cable
British CMA code equivalents
The British CMA codes often quoted by cable suppliers, are needless to say different to the harmonised codes. THe following table illustrates some of the common codes and their equivalent in harmonised form:
| CMA Code | Harmonised Code | Applicable standard | Comments |
|---|---|---|---|
| 2183Y | H03VV-F | Light duty 3 Core flex | |
| 6242BH | H05V4Z1-U | BS7211:1998 Table 7 | Twin and Earth, Low Smoke Zero Halogen (LS0H) |
| 6242Y | H05VV-U | Twin and Earth | |