Historically the UK used its own set of colour codes for fixed and flexible wiring. In the early 1970s the colours used for flexible wiring were harmonised across Europe, however the colours for fixed wiring remained unchanged until recently. In March 2004 the fixed wiring colours were also harmonised. During a transition period that began on 31st of March 2004 and ended on the 31st March 2006, use of either colour scheme was acceptable. Now only the harmonised colours may be used. The result is that it is now possible to encounter installations that use both colour schemes, and hence great care must be taken to ensure conductors are correctly identified when carrying out any work.
Conductor Colour Coding (single phase T&E) Conductor |
Old UK Colour |
Harmonised Colour |
Live (Phase) |
Red |
Brown |
Neutral |
Black |
Blue |
Earth or CPC |
Green / Yellow Stripe |
Green / Yellow Stripe |
Conductor Colour Coding (three phase / Triple and Earth / SWA) |
||||||
Conductor |
Old UK Colour |
Harmonised Colour |
2 Core |
3 Core |
4 Core |
5 Core |
Live 1 |
Red |
Brown |
X |
X |
X |
X |
Live 2 |
Yellow |
Black |
X |
X |
X |
|
Live 3 |
Blue |
Grey |
X |
X |
X |
|
Neutral |
Black |
Blue |
X |
X |
X |
|
Earth (CPC) |
Green / Yellow Stripe |
Green / Yellow Stripe |
X[1] |
[1][2] |
[2] |
X |
Notes
There is an IEE leaflet explaining these changes. That is available here
Installations that are wired using cables to both colour schemes should carry a warning sticker (see example) on or near the consumer unit that statesand looks something like this:
CAUTION This installation has wiring colours to two versions of BS7671. Great care should be taken before undertaking extension, alteration or repair that all conductors are correctly identified. |