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Electric Cable Colours: Wiring Colour Coding Standards

Electrical Cable Colours

ixed wiring electricity supply requires specific electrical cable colours to abide to government regulations (BS 7671). Cable colours are used to identify different power lines in different countries and different phases within three phase power supplies. Electrical cable colours are distinguished with either a dyed lead insulation sheath, electrical tape or an identifiable plug insulator.

New UK Wiring Colours

New Electrical Cable Colours were introduced in the UK in March 2006, when the United Kingdom’s government made an amendment to British Standard BS 7671 (Requirements for Electrical Installations). In three phase electricity, the UK use a set standard of tones to identify their cables. Wiring regulation BS 7671 harmonised UK wiring colours with European electrical cable colours for consistent standards across the continent.
UK & European Electrical Cable Colours
Region Earth (E) Neutral (N) Live 1 (L1) Live 2 (L2) Live 3 (L3)
Europe Green Blue Brown Black Grey
UK Green Blue Brown Black Grey

Old UK Wiring Colours

The changing of colour coding standards for electric cables is of the most significant changes for the electrical industry in modern history. The old wiring colour codes did not account for proper phase rotation, therefore most of Europe now abides by IEC (International Electrotechnical Commission) for single phase and three phase electricity.
Old UK Electrical Wiring Colours
Region Earth (E) Neutral (N) Live 1 (L1) Live 2 (L2) Live 3 (L3)
UK Traditional Green and Yellow Black Red Yellow Blue

H07RN-F Cable Colours

H07RN-F is available with either a single core design or multi-core design. Typically, single core mains cables are used for higher current ratings as one line will be used for each of the three phases plus neutral and earth. Standard multi-core lines are available with 2 cores, 3 cores, 4 cores or 5 cores, however some manufacturers offer rubber flexible cable variants with up to 19 conductive cores.

Multi-Core H07RN-F Wiring Colours

2 core: Blue (Neutral) and Brown (Live Line 1)
3 core: Green/Yellow (Earth), Blue, Brown
4 core: Green/Yellow, Brown, Black (Live Line 2), Grey (Live Line 3)
5 core: Green/Yellow, Blue, Brown, Black, Grey

Multicore Cable Colour Coding

Cable like H07RN-F will have a black outer sheath made of rubber PCP. As a result, within the cable there is a multicore centre that houses the conductors for electrical distribution. Although the number of cores may change, the UK wiring colours will remain the same.
2 core
3 core
4 core
5 core

USA Wiring Colours

The USA have their own electrical cable colours three phase or single phase circuits. Low voltage connections use black, red, and blue live lines. Alternatively, high voltage connections us brown, orange and yellow 480 VAC live lines.
USA Electrical Cable Colors
Region Earth (E) Neutral (N) Live 1 (L1) Live 2 (L2) Live 3 (L3)
USA Low Voltage Green White Black Red Blue
USA High Voltage Green Grey Brown Orange Yellow

USA Voltages

In the United States 2011 National Electrical Code (NEC) is the standard regulating most electrical installations. The National Electrical Manufacturer’s Association (NEMA) defines high voltage as over 100 to 230 kV.

US low voltage cable coding is applicable to voltages such as: 120V AC, 208V AC and 240V AC.
US high voltage cable coding is applicable to voltages such as: 277V AC, 480V AC.

Australian Wiring Colours

Australia have their own electrical cable colour standards as set by AS 3000. Australian engineers use red, white and blue for their live wire colours. The specific difference that is unique to Australia is the white L2 line.
Australian Electrical Cable Colours
Region Earth (E) Neutral (N) Live 1 (L1) Live 2 (L2) Live 3 (L3)
Australia Green Black Red White Blue
However, it is also permissible in Australia to use European colours in some circumstances according to AS 3000. It is possible that modern coding may incorporate a harmonisation with Europe.

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