Reference
UK cable colour codes — old vs harmonised
The UK adopted the CENELEC harmonised cable colours on 31 March 2004, with a two-year changeover period. Since 31 March 2006 all new installations, additions and alterations must use the new colours. Older installations remain legal, but where old and new colours coexist, a warning label is required by BS 7671 Regulation 514.14.1.
Fixed wiring (singles, T&E, SWA cores)
| Conductor | Pre-2004 | Harmonised (current) |
|---|---|---|
| Line 1 / Phase | Red | Brown |
| Line 2 | Yellow | Black |
| Line 3 | Blue | Grey |
| Neutral | Black | Blue |
| Protective (CPC / earth) | Green/Yellow | Green/Yellow |
Flexible cords (appliance flex)
Line
Pre-1970: Red
Modern: Brown
Neutral
Pre-1970: Black
Modern: Blue
Earth
Pre-1970: Green
Modern: Green/Yellow
Mixed-colour warning label
BS 7671 Regulation 514.14.1: where a distribution board or consumer unit contains cables of both the old and new colour codes, a warning notice must be affixed reading:
CAUTION
This installation has wiring colours to two versions of BS 7671. Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified.