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UK Wiring Colours – A Helpful Guide

If you’ve ever seen the inside of an electrical cable, you’ll have noticed that the wires inside are different colours. Have you ever wondered what each colour means and why they’re different in the first place? Well, we’re here to put your mind at ease and answer your questions!

In this post, we’ll take a look at the current wiring colours in the UK, what they were in the past, and why they’ve changed at all. So, keep reading!

Table of Contents:

So, if you:

  • Are curious about wires and the way they are coloured;
  • Want to know more about the evolution of British wiring;
  • Want to make sure your electrician is not changing old wires with other old wires.

Then this is the post for you!

A bit about electrical wiring

To understand the different colours, we’ll briefly talk about the wires themselves and what they do.

A standard electrical cable has three wires – live, neutral, and earth.

The live wire carries electricity to the appliance. The neutral wire, on the other hand, is there to take electricity away from it to avoid electrical overload. These wires together make a circuit.

However, these two by themselves can be very dangerous. When electricity travels around a property, it will always try to take the path of least resistance to the earth. If any of the two wires are damaged, contact with the appliance in question can cause electrocution, as the electricity will attempt to travel to the earth through your body.

That is where the earth wire comes into play. It has the essential safety function of connecting the appliance to the earth at all times, thus preventing the current from being transmitted to the metal casing.

So, these are the wires in a standard household electrical cable. Now let’s talk about their colours.

New wiring colours in the UK (since 2006)

In 2006, the colours of the live and neutral wires changed (more on that below). So, what are the current wiring colours in the UK? Well, that depends on whether it’s a two or three-core cable.

2-core and earth cable colours

These cables are commonly used around every household and consist of a live, neutral, and earth wire in the following colours:

  • Live – Brown
  • Neutral – Blue
  • Earth – Green and Yellow

3-core and earth wiring colours

Three-core and earth cables have a live, neutral, and earth wire, as well as an additional conductor. They are mostly used when two-way lighting is involved, namely when two switches are operating the same light. Their wiring colours are as follows:

  • Live – Brown
  • Additional conductor – Black
  • Neutral – Grey
  • Earth – Green and Yellow

Old wire colours in the UK (1977 – 2006)

Before 2006, the UK had its own wire colour code, which is now out of use. However, you can still find it in some houses with older wiring. If that’s the case in your home, we recommend that you get an electrician in to check the condition and safety of your wiring.

So, what were the old colours?

2-core and earth cable colours

  • Live – Red
  • Neutral – Black
  • Earth – Green and Yellow

3-core and earth wiring colours

  • Live – Red
  • Additional conductor – Yellow
  • Neutral – Blue
  • Earth – Green and Yellow
Before 1977, the earth wire was completely green, or bare.

Why are the live, neutral, and earth colours different?

As you can probably guess, the wires have different colours so that a person can easily tell them apart. This prevents any wiring disasters and accidental electrocutions.

If a live (brown) wire is not connected to the neutral and earth ones, there is a high risk of electrocution if you touch it. Before anyone attempts any electrical work, they must make sure no power source is connected to the live wire.

Electrocution upon contact with the neutral (blue) and earth (green/yellow) wires is unlikely; however, you should always exercise caution.

Needless to say, if you aren’t qualified, you shouldn’t attempt any wiring work around your house, as it can be hazardous to you and the safety of your home and family, consider hiring a certified electrician instead.

Why have the wiring colour codes changed?

In 2006, an amendment was made to the BS7671 Wiring Regulations, and the wiring colours in the UK were changed to comply with the specifications of the IEC 60446 international standard. This was done to harmonise the UK colours with the ones across Europe.

Harmonising the colours of wires helps avoid confusion, ensures that all European electricians’ qualifications are compatible, and facilitates the trade of electrical appliances across the border.

If there is an electrical installation where both the old and new wire colours are present, this should be specified at the fuse board or consumer unit with a warning.

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If your house needs rewiring, or if you need any electrical work done, it’s best to leave this to the professionals. The expert electricians at Fantastic Services are fully insured, certified, and sure to provide you with the highest quality service to ensure the safety of your property and family. So, leave the hard work in the hands of the experts, book an electrician today using our booking form!

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  • The standard domestic electrical cable has a live, neutral, and earth wire.
  • The current colours are brown for live, blue for neutral, and green and yellow for earth wires.
  • The UK wiring colours were changed in 2006 to harmonise them with the rest of Europe.
  • The colours of the wires are different to avoid confusion, wiring faults and accidental electrocutions.


Did you find this post useful? Do you have any interesting information about electrical wiring colours in the UK? Share it with us in the comments!

Image source: Polly Ivanova Illustration

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