The UK's wire colour coding system follows international standards set by the BS 7671 wiring regulations. This system has been in place since 2006, replacing the older colour scheme.

Here are the current colours used in a standard three-pin plug:

1. Brown – Live (L)

The brown wire carries the electrical current to the device. It's also known as the "hot" or "phase" wire and must be handled carefully as it is always live when the power is on.

2. Blue – Neutral (N)

The blue wire completes the circuit by returning the current to the power source. It is vital for balancing the flow of electricity.

3. Green and Yellow – Earth (E)

The green and yellow striped wire, often referred to as the "ground" wire, provides a safe path for excess current to prevent electric shocks or damage to the device.

Old Plug Wire Colours

Before 2006, the UK used a different colour code for electrical wiring. If you're working with older installations, you may encounter the following colours:

- Red – Live

- Black – Neutral

- Green – Earth

If you're replacing or repairing wiring in older systems, label the wires correctly to avoid confusion between the old and new systems.

Safety Tips for Plug Wiring

1. Turn Off the Power: Always disconnect the device from the mains before working on a plug.

2. Use the Correct Tools: A screwdriver and wire strippers are essential for safe and precise wiring.

3. Secure Connections: Ensure all wires are firmly connected to their corresponding terminals (L, N, E) to prevent loose connections or short circuits.

4. Check Regulations: Adhere to the latest BS 7671 standards for compliance and safety.

Conclusion

Understanding plug wire colours is essential for anyone working with electrical systems. Whether replacing a plug, wiring a socket, or troubleshooting an issue, knowing the standard colour codes can help a lot. If unsure, always seek the assistance of a qualified local electrician in London.