Electrical Wiring Colours in the UK

Electrical Wiring Colours in the UK

  • Post published:April 5, 2021
  • Reading time:3 mins read
Home > Electrical Wiring Colours in the UK

Are you confused by electrical wiring colours and want clarity on each one?

You need to be very cautious when handling electrical appliances, especially when attempting to wire them. If wired incorrectly, it could become an electrical hazard and even result in injury or death.

Fortunately, this can be avoided as long as you know the basics.

In this guide, we’ll cover single and three-phase wiring systems. We’ll help to identify the purpose of each wire as well as the current and past colours. So, by using this information you can keep safe when handling appliances.

Single-Phase Electrical Wiring Colours

A single-phase wiring system is commonly used in homes for plugs and small appliances. It’s made up of three wires and is a basic one circuit system.

What are new wiring colours?

The wires and colours are as follows:

Live Wire (Brown)

This is the wire which carries electricity to the appliance. If this is live and not connected to the neutral or earth wires, there’s a high chance of electrocution. So before handling this wire, ensure it is not connected to any power.

Neutral Wire (Blue)

In the UK, the neutral wire is blue and it carries electricity away from the appliance to prevent overloading. It’s found at the circuit end to enable connection once electricity has flowed around the live and earth wires. You’re unlikely to be electrocuted by handling this wire, but you should still be cautious.

Earth Wire (Green & Yellow)

The earth wire is vital for our safety as it connects the metal casing of the appliance to the ground. This stops the current from the live wire from being transferred to the casing. If the earth wire was absent then every time you touched the appliance you would be electrocuted.

It’s important to know that wiring colours changed in 2006 to align with mainland Europe. Ultimately this would help to prevent confusion and increased safety.

Source: RS Components

What are the old wiring colours?

Before 2006, UK electrical wiring colours were as follows:

  • Live (Red)
  • Neutral (Black)
  • Earth (Green & Yellow)

Since 1977, the earth wire has remained the same colour. But before this date, it was simply green.

Three-Phase Electrical Wiring Colours

A three-phase system is commonly used in motors, generators and other industrial appliances. It’s made up of four wires- three conductors and one neutral.

In 2006, the wiring colours changed as well to align with mainland Europe. Below is a list of the old and new colours:

Pre-2006

  • Phase 1 – Red
  • Phase 2 – Yellow
  • Phase 3 – Blue
  • Neutral – Black 

Post-2006:

  • Phase 1 – Brown
  • Phase 2 – Black
  • Phase 3 – Grey
  • Neutral – Blue

The benefit of a three-phase wiring system is that it offers a higher consistency of power compared to a single connection. This is why it’s used more for commercial purposes rather than domestic