The plug

The cable

A mains electricity cable contains two or three inner wires. Each has a core of copper, because copper is a good conductor of electricity. The outer layers are flexible plastic, because plastic is a good electrical insulator. The inner wires are colour coded and have different functions:

BrownLiveIs held at a voltage of 230 V and provides the current
BlueNeutralCompletes the circuit
Green and yellow stripesEarthA safety wire to stop the appliance becoming live

An earthed conductor cannot become live.

The wires

In a plug, the blue neutral wire goes to the left, the brown live wire to the right and the green and yellow striped earth wire to the top. The fuse fits next to the live wire.

The diagram shows the key features of a three-pin mains plug:

The inside of a plug showing the positioning of the earth, neutral and live wires, as well as the fuse and cable grip.

Where does each wire go?

There is an easy way to remember where to connect each wire. Take the second letters of the words blue, brown and striped. This reminds you that when you look into a plug from above:

  • blue goes left
  • brown goes right
  • striped goes to the top