Knowledge
Core colours according to HD 308
The harmonised colour codes and what happens from six cores.
HD 308 S2 fixes the core colours of low-voltage cable in Europe: green/yellow is always the protective conductor, blue the neutral, brown, black and grey the phases. From six cores the cores are usually black and numbered. Instrumentation cable has its own colour codes: on the RE types each pair has a black and a white core and a number.
HD 308 S2 fixes the core colours of low-voltage cables in Europe. In a cable with a protective conductor the green/yellow core is always the earth. That colour combination may not be used for anything else.
The usual sequence: two-core blue and brown. Three-core with earth blue, brown and green/yellow; three-core without earth brown, black and grey. Four-core with earth brown, black, grey and green/yellow; four-core without earth blue, brown, black and grey. Five-core with earth blue, brown, black, grey and green/yellow. Blue is the neutral where one is present.
From six cores the colour coding is usually dropped. The cores are then black with printed numbers, possibly with one green/yellow core. Instrumentation cable has its own colour codes. On the RE types to EN 50288-7 each pair has a black and a white core, a triad adds a red one, and pairs and triads are numbered. BS 5308 and NEK 606 use other pair colours. Control cable such as LiYCY follows yet another sequence, the DIN 47100 colour code.
Older installations do not follow that sequence. Before HD 308 S2, grey was not a phase colour and two phases could share the same colour. In British installations from before 2006 the phases may still be red, yellow and blue, with black as the neutral. Always verify by measurement; do not rely on the colour.
For the buyer: up to and including five cores the colours are fixed and you do not need to specify them. From six cores you do. State on the enquiry line whether you want numbered cores, the DIN 47100 code or the VDE 0815 one, and whether a green/yellow core has to be included. That is a different version per type, so it decides whether there is stock. If the cable joins an existing installation, tell us which code is already there: colours and numbers mixed in one terminal strip create work nobody wants to see again.
Does a cable have to join an existing cabinet or terminal strip? Send us the core marking as it stands, with the number of cores. We find the version with the same colour or number code.
In our cable selector, Cable selector tab.