UK Wiring Colours: A Complete Electrical Wiring Guide

Written by  Harry Taylor
Last updated: July 5, 2023

In order to avoid confusion and to encourage harmony, Amendment 2 of the 17th Edition BS7671 Wiring Regulations brought a change in the UK wiring colours and made it as the European wiring colours in 2006. This was also done to promote the business of electrical goods and to have compatibility in electrician’s qualifications in the UK and the mainland.

Let’s talk about the British wiring colours as they are now.

British Wiring Colours—Why Use Different Colours In The First Place?

If we consider the theory, an electrical appliance requires one wire to bring electricity to it. Imagine cutting the wire in half and connecting the electrical appliance in the middle. One wire brings electricity to the appliance, while the other takes it away. These are known as live and neutral wires respectively. These are your two wires, but what about the last one? The third wire is for safety precautions and is known as the earth wire. In order to reduce the chances of electrocution and house fires, the earth wire provides a connection to the earth at all times.

It is not just the residential buildings that have three-coloured wires in the UK, but there are three colours inside the actual appliance as well. This offers consistency when you work on various appliances with the appliance wiring colours the same as the plug wiring colours.

UK Wiring Colours – A Guide

Before we talk about the new wiring schemes in British, let’s state the old wiring colours just so you could have a little perspective.

In the UK, all the domestic electrical plugs had three colours: red, black, and green showcasing yellow stripes.


The colour of the live wire had been red.


The neutral wire used to be in the colour black.

Green With Yellow Stripes

The wire for earth used to be green before the year 1977. After that, it changed to green and yellow and is the same ever since.

Wiring Colours After 2004

In 2004, the previously used wiring colour schemes were phased out. Although residential buildings built before 2004 still have the same wiring colour schemes and are perfectly safe and effective to use if they are in good condition.

Here is the new wiring colour scheme in the UK:


The previously black neutral wire has been changed to blue.


The live wire, previously red, has been changed to brown.

Green and Yellow

These are the colours for earth wire.

Wires And Compatibility Across Equipment

The blue wire, or the neutral wire, is for taking electricity away from an appliance.

On the other hand, the brown wire takes electricity to an appliance. Both the blue and brown wires help in completing the circuit.

The earth wire, the green and yellow coloured one has an important role in providing safety to the circuit. When electricity travels around a building, it takes the least resistant path to earth. When the neutral or live wire has a fault such that it exposes a metal and it becomes live, there is a chance of electrocution since the electricity would want to find a way to the ground through the human body. The earth wire prevents this from taking place by offering earth for an appliance.

In terms of household wiring, most plugs in the United Kingdom have the three-wire colours listed above. The primary aim of this is to ensure that wiring is compatible across equipment and electrical wiring utilized in sockets and lamps, and their related circuits and mains.

Wire And Cable Conditions

In case you’re buying a home previously owned by someone else, or are renovating your own, the condition of electrical cables and wiring is one of the most important factors to consider for your safety. In order to protect your own and your family’s safety and health, it is crucial that you regularly have a check-up of the electrical circuits in your home.

Here are a few things you may check around your home:

  • Check to see if there are any burn marks or black marks around the light switches or wall electrical sockets. In case you notice burn marks, it is likely that the switch is wearing out and is causing spark while being operated.
  • You may also check if there is a burning smell around the switches, as the burning smell of rubber or plastic. This happens when the insulation of the wire breaks down and causes short-circuits.
  • The last thing you may check, and we highly recommend getting a professional in for that, is to remove the plastic cover from the sockets and take a look at the wiring behind it.

In case you notice red and black wires, it means the wiring schemes are old. These wires may or may not be wearing out. If you see the insulation on the wires cracking or crumbling, we highly recommend calling in an electrician for help.

Sometimes, you may notice that the wiring is perfectly fine, however, if your home has old wiring, it is better to have a specialist come in and check the health of it. Remember, there are only a few centimetres of wiring that you are able to see, but there is plenty more under floors, behind walls, and even above the ceiling. Therefore, you would need the help of an electrician to monitor that. And besides, the average lifespan of electrical cable insulation is more or less 30-40 years. If you have the old wiring installed, it is better that you keep checking them to be on the safe side.

Moreover, if your wiring has these cable sheathings, it also shows that the wiring is ancient.

Tough Rubber Sheaths

The PVC insulated cables became popular in the 1960s. Before that, most homes had Tough Rubber Sheaths (TRS). You may recognize this covering due to its black exterior.

This type of sheathing may worsen with age and temperature, as well as exposure to sunlight.

Lead Sheaths

Before the 1950s, lead-sheathed cables had been used in homes. These consist of copper conductors with a lead sheath insulated with rubber. Because they have rubber as the insulation, they are prone to wear out over time.

Lead sheathing is still utilized in old buildings, and if you have them, they may be worsening with time and you may have no idea about it. If this is the case, please consider calling in an electrician for an inspection.

PVC Sheaths

PVC sheaths came to the limelight in the 1960s and are still quite popular.

The Extensions In Your Home

You also need to know about the extension leads in your home. Till the 1990s, every house had one or two power points in most rooms. For example, in the lounge area, the electrical appliances were a TV, and perhaps a lamp. Similarly, in the kitchen, you would see a toaster and a kettle. Bedrooms would have a socket for lamps. These days, you need more than just these power sockets to fulfil our electrical needs. Therefore, in older houses, we use extension leads to increasing the power points in a room. However, in older homes, the power sockets had been designed to support a single appliance. When you plug in several devices at once through the extension, they drive more current and cause strain on the insulation.

If this thing is continued, you may have a house fire if you’re not careful. In modern wiring, we have circuit breakers and several power sockets in a room to prevent any issues with the electricity at your home.

How To Know If The Old Wiring Needs Replacing

It is important to keep an eye on the state of electrical wiring within your house to avoid risks including electrical fires and electrocution. There are some telling indicators that the wiring in your home will need to be changed, including:

  • If you see black marks or sparks and burning around ports, power sockets, light switches, and fittings, then the wiring needs to be replaced.
  • If you detect the odour of fire, the insulation that covers the wiring is likely to be burned out and in need of repair.
  • If you change the plug and find that the wires are black and red, then the wiring is ancient. In such circumstances, it is worth reconfiguring your wiring to bring them up to modern safety standards.
  • When you’re using a lot of electrical equipment and the electricity keeps running out, it’s possible that you’re overworking a circuit that might lead to overheating and electrical fire. In such situations, it may be worth hiring a skilled electrician to install extra sockets so that the electricity is more uniformly spread around your house.

Be Careful Of These Danger Signs

Electricity can be highly hazardous – and potentially fatal – if it is not treated properly. Ideally, all jobs requiring electricity must be done by a trained electrical worker.

However, if you’ve been contemplating doing DIYs around your home — even if it’s anything as basic as replacing a socket or even installing a new electric light — then it’s necessary to make sure you know some danger signals, including:

  • If you smell smoke, see fire or other black or charred-looking spots on any light fixtures, turn them off automatically, both on the walls and on the fuse box.
  • When you take the covering from the power switch to remove it or fit anything like a dimmer switch, ensure all the switches are turned off as well as on the fuse box.
  • If you’re going to rewire the electrical plug, ensure that the appliance and the plug are disconnected from the wall. You must also check that the three colour-coded wires are properly located in their appropriate pegs. Throughout the UK, if we look at the brass pegs on the regular 3 pin electrical socket, there are two square brass pegs aligned at the right angle to the plug (neutral and live) and the other rectangular brass peg oriented with the earth. At one end, the live wire (brown coloured wire) would be attached to the fuse, the blue-coloured wire would be attached to the other end, while the green and yellow one would be attached to the middle terminal. However, in case you aren’t sure of this, please seek the help of a professional.

Wrapping Up

In this article, we talked about the British wiring colour scheme as well as a few other things, such as the conditions of wires and cables, why colour schemes are used, how to know when you need to replace your wiring, the extensions in your home, the dangerous factors you need to consider in terms of the wiring in your home.

In case you’re noticing dangerous electrical symptoms in your home, or have recently moved into an old property in the UK, it is best to call in a professional for inspection.

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