Fixed Wiring Colours

The changes to the colour identification of conductors in fixed wiring colours are European Harmonised colours and were introduced as part of Amendment No 2 : 2004 to BS 7671 : 2001.

Single phase installations used the traditional colours of red and black for the phase and neutral conductors are replaced by the familiar colours of brown and blue (Regulation 514-03-01). A neutral conductor, where identified by colour, must be identified by the colour blue (Regulation 514-04-01). Protective conductors remain green and yellow (Regulation 514-04-02).

Three phase installations have traditionally used red, yellow and blue for the phase conductors and black for the neutral conductor. These are replaced by the colours of brown, black and grey for the phase conductors and blue for the neutral conductor (Regulations 514-03-01 and 514-04-01). Protective conductors remain green and yellow.

All installations starting after 31st March 2004 and before 1st April 2006 may be installed in accordance with Amendment No. 2 : 2004 or Amendment No 1 : 2002, in other words they may use the harmonised colours or the old colours but not both.

Extensions, alterations or repairs to existing wiring

An extension, alteration or repair to an existing single-phase installation should be wired in the colours of brown, blue and green and yellow. If any of these changes are made to an installation that results in both the old and new wiring being present, a warning notice must be affixed at or near the appropriate distribution board or consumer unit (Regulation 514-14-01).

An extension, alteration or repair to an existing three phase installation should be wired in teh colours of brown, black, grey, blue and green and yellow. Old and new phase conductors should be fitted with sleeves marked L1, L2 and L3 and neutral conductors should be fitted with sleeves narked N to avoid any possible confusion. As with the single phase installation, where changes result in both the old and new wiring being present, a warning notice must also be affixed at or near the appropriate distribution board or consumer unit.

Identification of Conductors

Function Alpha Numeric Colour
Protective conductors Green and yellow
Functional earthing conductor Cream
AC Power Circuit(1)
Phase of single-phase circuit L Brown
Neutral of single- or three-phase circuit N Blue
Phase 1 of three-phase circuit L1 Brown
Phase 2 of three-phase circuit L2 Black
Phase 3 of three-phase circuit L3 Grey
Two-Wire Unearthed DC Power Circuit
Positive of two-wire circuit L+ Brown
Negative of two-wire circuit L- Grey
Two-Wire Earthed DC Power Circuit
Positive (of negative earthed) circuit L+ Brown
Negative (of negative earthed) circuit(2) M Blue
Positive (of positive earthed) circuit(2) M Blue
Negative (of positive earthed) circuit L- Grey
Three-Wire DC Power Circuit
Outer positive of two-wire circuit derived from three-wire system L+ Brown
Outer negative of two-wire circuit derived from three-wire system L- Grey
Positive of three-wire circuit L+ Brown
Mid-wire of three-wire circuit(2)(3) M Blue
Negative of three-wire circuit L- Grey
Control Circuits, ELV and Other Applications
Phase conductor L Brown
Black
Red
Orange
Yellow
Violet
Grey
White
Pink, or
Turquoise
Neutral or mid-wire(4) N or M Blue

(1) Power circuits include lighting circuits.
(2) M identifies either the mid wire of a three wire d.c. circuit, or the earthed conductor of a two wire earthed dc circuit.
(3) Only the middle wire of three-wire circuits may be earthed.
(4) An earthed PELV conductor is blue.