3 Core Cable Colours?

Both 2 and 3 core cable have specific colour requirements. In March 2004,British Standard BS 7671, dealing with electrical installations, saw some changes to 2 core and 3 core colours in UK. These changes in standards took effect from April 1st 2004. So, for instance, prior to April 1, you would have seen cable manufacturers selling 25mm 3 core armoured cable with different colours, but after the new standards took effect, it is illegal (since April 1 2006) to sell or use those cables with older colouring schemes.

Until end of March 2004, the 3 core & earth cable colouring standard was blue, yellow and red, with earth. However, post March 2004, the new 3 core cable colours are grey, black and brown with earth. These colour standards didn’t come into force overnight – there was a 2-year overlap (grace) period before the switch became mandatory. In the interim, retailers sold 2-core and 3 corearmoured cable, and other types of three-core products, with old as well as new colouring system.

So, why was this colouring standard changed? It was primarily to synchronise cable colours with the rest of European Union countries. Now, a unified colour code is in effect across all Euro nations, as well as the U.K. Under the new system, if your application calls for the use of a product such as a 3 core flat cable, it will only be sold in the new colouring code across the continent.