Electrical Wiring Colours In The UK: A Complete Guide

Written by  Harry Taylor
Last updated: January 16, 2024

Electrical wiring colours in the UK can be confusing. There are at least 5 of them: blue, green and yellow, red, black and brown. All electrical connections only need three types of wires. So, it’s understandable for people to get confused.

This article will clear up that confusion by exploring the meanings and reasons behind each electrical wiring colour. We will even provide tips for identifying wires that need replacement.

The Different Types of Wires in an Electrical Connection

As stated in the introduction, all electrical connections need three types of wires. These three are live, neutral and earth wires. Here is a brief explanation of each one.

  • Live: The live wire transmits electrical current from a power source to an equipment or appliance.
  • Neutral: The neutral wire returns electrical current to the power source from the equipment or appliance.
  • Earth: The earth wire is a safety feature that provides a connection to the earth. This connection is crucial when issues (like exposed wires or electrical faults) occur. When such issues occur, electricity wants to return to the earth. It would try to do so through the path of least resistance. The earth wire provides this pathway. Without it (earth wire), the risks of electrocution and fires increase.

All electrical connections need these three types of wires. More than anything else, they need the two main ones, the live and the neutral wires. So, you will find this wiring scheme in every electrical system, power source, appliance or equipment.

It’s just that the colour scheme might be different. The colours representing each type of wire might be different. Fortunately, the point of this article is to help you understand all electrical wiring colours.

What are the new UK wiring colours?

These new colours exist because the authorities changed the UK’s electrical wiring colour scheme in 2006. Here are the UK’s new electrical wiring colours.

  • Live: Brown
  • Neutral: Blue
  • Earth: Green and yellow. The earth wire is the only one that was never changed.

What are the old UK wiring colours?

Here are the old electrical wiring colours in the UK.

  • Live: Red
  • Neutral: Black
  • Earth: Green and yellow or naked. The colour of the earth wire has remained the same since 1977.

When and why did the UK’s electrical wiring colour scheme change?

The UK changed its electrical wiring colour scheme in 2006. The authorities did this via Amendment 2 of the 17th Edition BS7671 Wiring Regulations. They did this to create harmony between the UK’s and the European Union’s electrical colour schemes. This change reduced confusion and made the UK’s electrical appliances and electricians more compatible with those of the EU. 

The change actually started in 2004. At that time, the old electrical colour scheme was slowly being replaced. However, those old colours became illegal when the amendment was made in 2006. Every building, appliance and equipment must now use the new electrical wiring colour scheme. Old buildings, appliances and equipment must also be updated.

However, it’s normal to run into the old electrical wiring colour scheme occasionally. It means the building was wired before 2006 and never updated. Sometimes, you might find both the new and old electrical wiring colour scheme in the same system.

The old electrical colour scheme indicated that those wires are at least 17 years old. The average lifespan of electrical cable insulation is more or less 30-40 years. Therefore, those old wires might still be healthy. However, it’s safer and more convenient to replace them and adopt the new electrical wiring colour scheme. Other indicators that a wire is old are tough rubber and lead sheaths.

Besides, old wiring systems don’t always have the capacity for modern needs. Old systems often have just two power points per room. As a result, you might need extensions to plug all your gadgets and electronics. This creates another problem because some old wiring systems aren’t designed for that much workload. They might also lack the safety measures (like circuit breakers) present in new wiring systems.

Here are indicators that electrical wires need to be replaced.

  • Black marks or sparks and burning around ports, power sockets, light switches, and fittings
  • Odour of fire
  • Old electrical wiring colours
  • Electricity keeps running out

Single VS 3 Phase Wiring colours in the UK

Single-phase connections have three wires: one live, one neutral and one earth wire. Three-phase connections have four or five wires: three live wires, a neutral and an earth wire. The earth wire is not included every time. So, sometimes, three-phase connections have four wires only.

In 3-phase connections, electrical current is alternated between the live wires. This reduces the risks of overloads, allowing the system to handle up to 415 volts, while single-phase connections can only handle 230 volts. As a result, 3-phase connections are popular in commercial buildings with heavy machinery. Single-phase connections are more popular in residential buildings.

The following tables show the new and old electrical wiring schemes of single and 3-phase connections. 

Table 1: Single-Phase Electrical Wiring Colours

Wire TypeNew Electrical Wiring ColoursOld Electrical Wiring Colour
EarthGreen and yellowGreen and yellow

Table 2: Three-Phase Electrical Wiring Colours

Wire TypeNew Electrical Wiring ColoursNew Electrical Wiring Colours
Phase oneBrownRed
Phase twoBlackYellow
Phase threeGreyBlue
Neutral BlueBlack

Wrapping Up

Electrical wiring colours in the UK are brown (live), blue (neutral) and green and yellow (earth). When the live wire is red and the neutral is black, you are dealing with the old electrical wiring colour scheme. It could also mean that your wiring system is old and should be replaced.

An old electrical wiring colour scheme doesn’t necessarily mean that wires are unhealthy. However, everything deteriorates with age. So, we recommend hiring a professional to examine those wires and tell you if you don’t need to replace them.

You can conduct the inspection yourself, especially since we have already shared some warning signs with you. However, it’s always better to hire a trained expert. Either way, remember to turn off power and disconnect appliances before messing with electrical wires.

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