When Did Wiring Colours Change?

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For this section we will look at how wiring colours have evolved over the years. We will discuss how often the colours of wiring have changed in the UK and the reasons behind these changes. British wiring colours have changed for reasons of safety and to harmonise UK wire colours with other countries. British wiring colours have seen small changes several times in recent generations although a major overhaul occurred once in the mid-2000s.

Minor wiring colour changes occurred in the UK shortly after the second world war, in the 1960s and during the 1970s. The purpose of these changes was primarily safety with wiring colour changes occurring such as the white second phase wire being changed to yellow in 1964. 

 

These minor changes helped to reduce confusion and therefore increase safety. The UK first adopted the IEC wiring colour standard in 2004. However, these changes did not fully come into effect until March 2006. Officially, these changes were brought in under British Standard BS 7671.

The main reason for these changes was to match UK wire colours with those in Europe in order to achieve harmonisation. The implementation of these new IEC-based rules resulted in the neutral, single phase live and three-phase live wiring colours all being changed. Only the protective earth wire retained its pre-IEC colour, that being green and yellow.

New Wiring Colours

We will now lay out the details of UK wiring colours since the IEC rules came into effect. Current wiring consists of green/yellow, blue and brown wires. This colour code entails a live wire that is brown, a blue neutral wire and a green/yellow protective earth (PE) wire. Modern wiring colours are the result of the 2004-06 overhaul of wiring colours in the UK. The law since 2006 stipulates that these colours must be used for any wiring in new electrical installations. As a result, old wiring can still be found in pre-2006 installations.

Green/Yellow Protective Earth Wire

The PE wire has remained a mixture of green and yellow since 1977 and did not undergo any changes in the 2000s. A PE conductor exists for safety purposes and is designed to send a current straight to the ground if needed. This can prevent electrocution. 

Brown Live Wire

The colour of the live wire changed from red to brown as part of the new regulations. If you find a red live wire in any of your appliances it means that the item uses old wiring. A live wire is that which carries an electrical current.

Black Live Wire

The 2004 changes also saw three-phase live wires change colours. A black live wire can be found as line 2 in three-phase wiring. It replaced a yellow live wire which was the standard line 2 colour prior to 2004.

Grey Live Wire

The grey live wire is line 3 in three-phase wiring. Previously the line 3 live wire was blue before the IEC rules were implemented a decade and a half ago.

Neutral Blue Wire

The neutral wire colour changed from black to blue as part of the IEC rules. Neutral wires are designed to regulate and manage voltage. They have the ability to return currents to the power source. The aforementioned brown live wire forms a complete circuit with the neutral blue wire.

3 Core and Earth Cable

A 3-core and earth cable are one of two common types of wiring systems. This type of wiring system is deemed appropriate for Appliance Class I, meaning any appliances with connectivity to earth. The internal 3-core and earth electrical cable colours comprise a live brown wire, a neutral grey wire, a green/yellow protective earth wire and an additional black conductor which we have discussed as the live line 2 wire.

2 Core and Earth Cable

2-core and earth cables are considered appropriate for Appliance Class II, inferring that they are suited for appliances which lack connectivity to earth. A 2-core and earth cable consist of a live brown wire, a neutral blue wire and a green/yellow PE wire.

Old Wiring Colours

In this section, we will explain what colours were used for pre-IEC wiring in the UK. By law, electrical wire colours for new installations from 1977 to 2004 were composed of a green/yellow earth wire (or a bare copper wire) and black and red wires which were the neutral and live wires respectively. These electrical wire colours comprised the IEE wiring colour regulations prior to the introduction of European harmonisation in the 21st century.

Green/Yellow Protective Earth Wire

The only change introduced in the 1970s to the IEE colour regime concerned the PE wire. The earth wire colour changed from pure green to green/yellow wire colours in the UK, a combination which it retains to date. The UK also used a black earth before World War II.

Red Live Wire

Until 2004, the live wire colour was red for any new installations. This wire did not see any changes in 1977 and had been the standard colour of British line 1 live wires for generations.

Yellow Live Wire

Before the introduction of BS 7671, line 2 in any three-phase wiring was yellow. Line 2 had also been white pre-1964.

Blue Live Wire

Prior to 2004, the line 3 of three-phase wiring was blue. Line 3 was blue for several decades although it was green prior to the second world war.

Neutral Black Wire

All new neutral wires were black before 2004. This had not changed in 1977 and black had been the colour used in new UK electrical appliances for many decades prior.

3 Core and Earth Cable

Old 3-core and earth cables consisted of a live wire that was red, a neutral blue wire, a green and yellow protective earth (from 1977 onwards) and an additional yellow conductor, which was the previous standard for the second line live wire.

2 Core and Earth Cable

2-core and earth cables used to comprise a live red wire, a neutral black wire and either a green and yellow or bare copper PE wire. The latter had previously been either bare or pure green as part of the pre-1977 IEE rules.

What Are the Plug Wire Colours?

We will now look at plug wiring colours, both old and new. Plug electrical wiring colours refers to the wire colour code found inside a given plug. These colour codes can vary depending on whether the plug contains old or new wiring.

Old Wiring

Old plug wiring consists of a red live wire, black neutral wire and a green/yellow or a pure green PE wire. In some cases, the PE wire may appear as bare copper. The red live wire extends from the cable grip to the live terminal while the black neutral wire travels from the neutral terminal to the cable grip and the protective earth conductor connects the cable grip to the earth terminal.

New Wiring

Plugs with modern wiring contain a brown wire that is live, a blue neutral wire and a green/yellow PE wire. Broadly speaking, the wiring connections in new plugs are the same as in old ones but with different colours for the neutral and live wires. Distinctions between old and new wiring can also apply to the PE wire if compared to an old green or bare copper wire. The live brown wire travels from the cable grip to the live terminal, the blue neutral wire from the neutral terminal to the cable grip and the yellow/green protective earth wire from the cable grip to the earth terminal. 

Condition of Electrical Cables

It’s important to know the condition of electrical cables in your home. This will allow you to know when your household should be rewired. In this section, we will discuss topics such as the materials used in old and new wiring.

 

Most modern wiring uses thermoplastic insulation. It’s also common for non-metallic sheathed cables to be present on the insulation. Synthetic polymer insulation is often used for underground electrical installations. The majority of conductors these days are made from copper although plenty of electrics still use aluminium conductors. Old wires were often made from aluminium or copper. Dated cables are usually coated in black rubber, lead or fabric. The best way to test the condition of your electrical cables is to have an electrical installation condition report (EICR) produced. 

 

A hired electrician can test your electrics and produce an EICR. The results of this report will allow you to understand the condition of your electrical wiring. An electrician undertaking an EICR inspection will look for signs of damage and perform electrical tests among other checks. If the EICR shows that there are faults, damage or other issues with your house’s wiring you should have it rewired and, in some cases, you may be legally required to. Even before having an EICR produced, if your household is more than a quarter of a century old this may indicate that you should have your house rewired. If you are blowing fuses or the breaker keeps tripping, these events may signify that your wiring is in bad condition. Other signs that your household’s wiring is in poor condition include lights flickering or dimming when an appliance is turned off and the appearance of staining or discolouring on an electrical outlet.

Frequently Asked Questions regarding a
Domestic Electrical Installation Condition Report

It is now a legal requirement for Landlords (Domestic and Commercial) to have the installation inspected and tested at least every five years or when occupancy changes.

It is recommended that private properties get an EICR every 10 years and it is now mandatory that Landlords have the installation inspected and tested at least every five years – and more often if the most recent safety report requires it.

An NICEIC accredited at approved contractor level, or approved by another electrical regulatory body at a similar or higher level - you can check this on the Electrical Safety Register.

The electrician will make a visual assessment, and then carry out a series of checks on your electrical systems. Any ‘code one’ problems, ie problems that are immediately dangerous, they will need to fix those there and then or at least make them safe. Any ‘code two’ problems that are potentially dangerous will be noted and a quote provided to fix them at the end of the process, and any ‘code threes” (Issues not deemed unsafe) will again be noted and quoted for. 

Each property is different but the electrician needs to check each area thoroughly so you should expect them to be there for a significant period of time. A visual check alone can take up to an hour, and it can take another hour to fill out the certificate.

  1. Be aware that your electrician will need to turn the power off before working on the wiring. You will not have access to any electrical gadgets, so it may not be the best day to work from home. It might be easier to let them in and leave them to get on with it for a few hours. It is possible to put circuits back on once they’ve been tested, but it will slow down the process.
  2. Ensure your electrician has free access to all lights, sockets and light switches. This means clearing areas where they will need to work before they arrive (children’s bedrooms, lofts and offices can be tricky).
  3. Don’t expect your electrician to issue you with a quote for remedial works immediately. It will take approximately 48 hours to process the data from the check itself before they can do this. It can take longer, particularly if you need extensive remedial works, which require a further visit from your electrician to discuss options before they can issue a quote.

You have a duty of care to your tenant and must ensure that the installation is safe when they enter the property and is maintained throughout their tenure.

The Landlords and Tenants Act (1985) requires that the electrical installation in a rented property is:

  • safe when a tenancy begins and
  • maintained in a safe condition throughout the tenancy.
  • We recommend that in order to comply with this Act, you get a registered electrician to carry out an Electrical Condition Report (EICR) on any property you intend to let before getting tenants in. This will certify whether the electrics are safe and tell you if anything needs upgrading.

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Where a report rates the electrics as ‘unsatisfactory’, the regulations require the landlord to undertake further investigative or remedial work by a qualified person within 28 days, or sooner if specified in the report. 

Unsatisfactory codes shown on the EICR report can include: 

  • C1 Danger present, risk of injury, immediate remedial action required 
  • C2 Potentially Dangerous, urgent remedial action required 
  • F1 Further investigation required