New Electrical Wire Colours and UK Wire Colours

08-08-2020 15:33 jay999#1
To harmonise wire colours, 2-core cable changed from live red to live brown, neutral black to neutral blue and earth remaining bare or green/yellow. 3-core cable was changed from red live to brown live, neutral blue to neutral grey, additional from yellow to black with earth bare or green/yellow.

To harmonise wire colours, 2-core cable changed from live red to live brown, neutral black to neutral blue and earth remaining bare or green/yellow. 3-core cable was changed from red live to brown live, neutral blue to neutral grey, additional from yellow to black with earth bare or green/yellow.

Why Have Wire Colours Changed?
28 years ago the United Kingdom agreed to adopt the colour blue for neutral conductors in flexible cables and flexible cords usually used for non fixed installations.

At that time no move was made to harmonize the colours for fixed installations. The rest of Europe however was changing over very quickly.

Home > DIY How To Projects and Tutorial Guides > New Wiring and Cable Colours – New Electrical Wire Colours and UK Wire Colours



New Wiring and Cable Colours – New Electrical Wire Colours and UK Wire Colours
In this DIY guide learn about the new standard wiring colours for electrical wiring and house wiring. We show you how the new wiring colours translate to the old electric wire colours and how you can ensure that the right wires are connected in any instance.

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To harmonise wire colours, 2-core cable changed from live red to live brown, neutral black to neutral blue and earth remaining bare or green/yellow. 3-core cable was changed from red live to brown live, neutral blue to neutral grey, additional from yellow to black with earth bare or green/yellow.

Before this change, old wiring colours in the UK for 2-core wire were red = live, black = neutral and earths are either bare or yellow and green, whereas with 3-core cable live = red, blue = neutral, additional = yellow and earth either bare or yellow and green.


Why Have Wire Colours Changed?
28 years ago the United Kingdom agreed to adopt the colour blue for neutral conductors in flexible cables and flexible cords usually used for non fixed installations.

At that time no move was made to harmonize the colours for fixed installations. The rest of Europe however was changing over very quickly.


In 1999 it became apparent that a new European standard for wiring and cable colours meant that the UK would have to catch up pretty quickly and change fixed cable colours to suit.

Obviously millions of existing cables had the existing red, black and yellow/green colours installed and to limit the number of installations where new circuit additions would mean mixing the colours, it was agreed that (even though the new regulations did not become compulsory until 31st March 2006) from 31st May 2004 the new cable colours could be used.

On this date the Institute of Electrical Engineers published Amendment 2 to British Standard 7671:2001 (The wiring regulations).

The amendment specifies the use of new cable colours for all new fixed wiring electrical installations in the UK. These new colours are sometimes referred to as Harmonized colours. They bring the UK more closely in line with practices in mainland Europe.

What Have Wire Colours Changed to?
Very simply the changes mean that fixed cables in your home will (if any new circuits are introduced) carry the same colour wires as any flexible cables you have:

In domestic wiring situations, there are essentially 2 different types of cable you will encounter; 2 core and earth and 3 core and earth. 2 core and earth (or twin and earth as it’s also known) is generally used for wiring radial and ring main circuits whereas 3 core and earth is used mostly in 2-way lighting setups.

The live Red becomes Brown
The Neutral Black becomes Blue
The Earth wires continue to be Green and yellow