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What Are The Electrical Wiring Colours In The UK?

The UK follows International Electrotechnical Commission standards and conformity for all fields of electrotechnology.

Electrical wiring is regulated to ensure it can operate safely. And must follow specific directions and standards. Wiring for AC and DC power distribution circuits are colour coded to allow for easy identification of individual wires.

What are the electrical wiring colours in the UK? Read on…

Electrical Wiring Colours

Old Electrical Wiring Colours

A red electrical wire was used to signify a live current. The neutral wire colour was black. And green and yellow wires were earth wires. Both red and black electrical wires are now illegal and any outdated wires must be replaced by a qualified electrician.

Other old UK power circuit wiring colour codes include line functions in 3-phase that were yellow and blue.

Wiring Colour Changes

Old electrical wiring colours were changed in the UK in 2006 when it became a legal requirement to bring the colours of electrical wiring in the UK in line with the rest of mainland Europe. Prior to this date, it was optional, and electricians were able to use new wiring colours from 2004.

Properties built before this date will probably contain the old wires. If you move into a home that has a mix of old and new wiring a warning notice will be visible on the applicable sockets or consumer unit to avoid confusion. It’s advisable to get colours and condition of these wires checked by a qualified electrician.

Correct House Wiring Colours

Electrical wiring colours are now:

  • Brown for the live wire – always located in the plug to the right;
  • Blue for the neutral wire – always located in the plug to the left;
  • Yellow and green for earth wires – located through the centre of the plug and up to the top;
  • L1 3-phase power circuit wiring is brown;
  • L2 3-phase is black;
  • L3 3-phase is grey.

Other Frequently Asked Questions

What colour is the live wire?

The live wire in your property should be brown. If it’s a red wire then it’s old and needs replacing immediately.

What is the job of the live wire?

The live wire carries the current into an electrical device at a high voltage. And is used by most home appliances. The live wire carries the current to the device – and the neutral wire carries it back. If the live wire is handled your body will act as a conductor for the active voltage being carried – and you can be electrocuted.

What does the earth wire do?

This is the safety device that connects the metal surrounding your appliance to the ground and stops the live wire from feeding current directly onto the device casing. Earthing is used to protect you from an electric shock by providing this path to earth – designed specifically to prevent shock. In the event of a fault, this current is enough to trip the circuit breaker or blow a fuse.

What is the grey wire in electric UK?

The National Electrical Code states that grey wire must be used for neutral conductors. These wires may still carry power that can give an electric shock and injure you. Neutral wires deliver power back to the service panel.

The standard grey wire is known as the Line-phase 3 in its AC code. Line voltage is seen on the AC line, which is typically single phase. Line current results from a voltage applied to a load – if you have a phase 3 line then each of the separate wires has its own voltage.

Electrical wiring- different colors

What is cable sheathing?

Cables in older properties were housed in an outer cover known as a sheath often made of tough rubber. This sheathing can deteriorate with age, excessive temperatures, and from direct sunlight. When this happens, the sheathing may become dry and break – losing insulation and flexibility. And will need replacing by a trained electrician.

Lead sheathing on cables are now past their working life and need to be inspected and safely replaced. Properties built since the 1960s will have PVC-insulated sheathing that won’t deteriorate over time.

Call in the Professionals

When you don’t have much knowledge about electrical wire colour code you need to get the help and advice of an expert. Trusted 24-hour emergency electricians will fault-find and problem-solve so that you don’t have to worry. And re-wiring alongside new installation will be carried out safely by a registered electrician.