What is the Wiring Colours Electrical Wire Colour Standards ?

Electrical wiring colours for three phase electrical applications are standardised to aid the identification of individual wire phases. Wiring colour codes for AC and DC power distribution circuits have changed on numerous occasions and vary depending on region.

or three phase electricity supply, circuits will use five wires: earth wire, neutral wire, live wire, line 2 wire, line 3 electrical wire. This article details the following cable colour codes:
    - International Wiring Colours
    - European Wire Colour Standards
    - Old & New UK Wiring Colours
Fixed wiring electricity supply requires specific wiring colour regulations (bs 7671) to identify different power lines in different countries. The USA have their own wiring colours for electrical circuits, black, red, and blue are used for 208 VAC three-phase; brown, orange and yellow are used for 480 VAC. Australia also have a different wiring colour standard. The UK's new cable colours for plugs are now harmonise with Europe's power cable colours for AC & DC. Most of Europe abides by IEC ('International Electrotechnical Commission') electrical wiring colours code for AC branch circuits.



Old & New UK Wiring Colours

When did UK wiring colours change?
In March 2006, the United Kingdom government made an amendment to British Standard BS 7671 (Requirements for Electrical Installations), as a result, the change of colour coding for electric cables was considered one of the most significant changes for the electrical industry in modern history. Wiring Regulations saw a change to harmonise the UK wiring colours with European cable colours for consistency and to avoid confusion. The old cable plug colour codes did not account for proper phase rotation, therefore most of Europe now abides by IEC (International Electrotechnical Commission) wiring colour codes for AC circuits.

What are the old UK wire colours?
In 1977, CENELEC published Harmonised Document 324 S1, covering the identification of insulated and bare conductors by colours. In 1999 it became apparent that a new European standard for wiring and cable colours meant that the UK would have to change fixed wire insulator colours. As a result, old UK wiring colours were required to change the red live wire and a black neutral wire.



Old Colour New Colour
Live Red Live Brown
Neutral Black Neutral Blue
- The old UK black neutral wire colour was replaced by a blue neutral wire.
- Old UK red live wire colour was replaced by a brown live wire.
- The UK earth wires are identified by green and yellow earth wires

How did UK wiring colours change?
The United Kingdom now follows the BS 7671 IEC AC plug cable colour codes. The UK fixed wiring colour standards are now universal in Europe like socapex wiring circuits, similarly this will be reflected on power connectors that are colour coded. Electricity supply for existing installations in households must be checked for old wires as this can cause considerable danger. Household plugs can be wired with three insulated wires.



What colour is the UK earth cable?
The UK and Europe's earth wire cable colour is green.

What colour is the UK neutral cable?
The UK and Europe's neutral wire cable colour is blue.

What colour is the live wire?
Live wire cable colours in the UK and Europe are brown

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