In the UK we operate on a 230 volts electricity supply which has the power to kill if it’s not used sensibly. Electrical appliances, circuits, leads, plugs etc. are specially designed to reduce the chances of you receiving an electric shock; but only if they are managed correctly.
We don’t all need to know how to manage electrical circuits correctly, that’s why we have electricians but we should understand the basics, like wiring a plug.
Wiring a plug
Everyone should understand the basics of a correctly wired 3-pin plug, and also be able to recognise any errors. If you don’t then this guide is for you. This is an image of an incorrectly wired plug, can you see what’s wrong?
The main issue here is the Live (brown) and the Neutral (Blue) wires are wired incorrectly; they should be opposite to what they are. The other issue with this picture is the cables have been clamped incorrectly – the white outer sheath should come into the plug casing and be firmly fixed in place by the clamp (the black part to the left).
A mains electricity cable contains two or three wires; these are commonly called “twin”, or “twin and earth”; each cable has a copper wire inside because copper is a good conductor of electricity. The outer layer (what we tend to refer to as the “wire” is flexible plastic, as plastic provides good insulation; this is wire the cable is commonly referred to as the “flex”; short for the “flexible cable”. The inner wires of the flex are are colour coded:
- The Blue wire is Neutral
- The Brown wire is Live
- The Green and Yellow striped wire is Earth
The plug itself has 5 main features:
- The plugs case is made of tough plastic or strong rubber as these are both good for insulation and thus protect the user
- The plug has 3 pins, made from brass, which is a good conductor, and strong
- The plug has a fuse between the live terminal and live pin
- If too much current flows from the electricity supply into the plug the fuse breaks the circuit
- The cable is secured in the plug by a cable grip
How to wire a plug
Wiring a plug is an easy process, sometimes fiddly though. You’ll need a screwdriver and perhaps a set of ‘snips’:
Let’s presume for this exercise that the wires have been prepared so we can use this easy is easy to remember saying:
Blue goes left, brown goes right and striped goes to the top
If you see the second letter of each wire relates to where it goes in the plug
bLue – left
bRown – right
sTriped – top
This diagram shows a correctly wired 3-pin plug