Wiring a Plug

The UK mains electricity supply is about 230V and can kill if not used safely. Electrical circuits, cables, plugs and appliances are designed to reduce the chances of receiving an electric shock. The more electrical energy used, the greater the cost. Electrical supplies can be direct current (d.c.) or alternating current (a.c.).You should know the features of a correctly wired three-pin mains electricity plug and be able to recognise errors in the wiring of a plug.

Most accidents with electricity in the home are caused by faulty or incorrectly wired plugs. The correct wiring of a plug is extremely important for your own safety.

Firstly strip off about 4cm of the outer cable sleeve. Slit the sleeve of the cable lengthways with a sharp knife, being careful not to cut into the coloured wires. Peel the outer sleeve away and cut it off.

cut back the outer cable sleeve

Separate the wires and cut to length using wire cutters. Use the plug as a gauge to cut the wires to the correct length. Leaving the wires the same length usually results in the live and neutral wires becoming crushed when the plug cover is replaced.

use the plug as a gauge to cut the wires to the correct size

Remove about 5mm of insulation from the end of each wire using wire strippers/cutters, be careful not to cut into the individual strands of wire. Now tightly twist the ends of the wires.

strip back about 5mm of insulation and twist tightly

Connect each wire to the correct terminal. Slacken the screw and push the bare wire into the hole. Re-tighten the screw. Make sure the terminals are tight and that there is no bare wires or loose strands of wire showing. It is often easier to push the pins up slightly when connecting the wires.

  • Brown - Live
  • Blue - Neutral
  • Yellow and green - Earth

Older appliances may have different colours:

  • Red - Live
  • Black - Neutral
  • Green - Earth
plug wired correctly

Tighten the cord clamp over the cable sleeving. Make sure the cord clamp is gripping the outer sleeve of the cable, not the coloured wires.

lighten the cable clamp securely

Check that a correct rated fuse is fitted. There are three standard fuse ratings- 3A, 5A & 13A.

  • For appliances up to 700W a 3A fuse is used.
  • For those between 700W and 1200W a 5A fuse is used.
  • For appliances over 1200W a 13A fuse is used.

Modern electrical appliances will have a sticker or plate showing the maximum power consumption in WATTS (W).

3 standard fuse types

Make sure there are no loose strands of wire in the plug. Check the wires are laying in the correct channels and will not become crushed when the cover is replaced. Double check that the wires are in the correct terminals and then replace the plug's coverand tighten the screw

replace the cover

Some appliances will only have two wires - Live & Neutral. These are 'Double Insulated' and do not rely upon the Earth wire for protection. The plug is wired as above but there is no Earth wire to connect, however make sure that the screw on the Earth terminal is not loose.

class 2 equipment does not require the earth wire