Three wires run into most mains appliances, each with a job and a colour. Two carry the working current; the third does nothing at all until something goes wrong, and then it saves a life.
The mains supply uses a live wire (brown), a neutral wire (blue) and an earth wire (green and yellow). A fuse or trip switch in the live wire breaks the circuit if too large a current flows, and the earth wire keeps a metal case safe if a fault makes it live.
The mains has a live wire (brown) that carries the supply, a neutral wire (blue) that completes the circuit, and an earth wire (green and yellow) for safety. A fuse or trip switch in the live wire breaks the circuit if the current is too large.
The earth wire carries fault current safely away if the metal case becomes live, blowing the fuse.
Connect the live, neutral and earth to their correct terminals and see how a fault is made safe.
Four quick checks. Each correct answer earns XP and lights this skill on your star map.
The live wire in a UK-style mains cable is coloured...
The earth wire is coloured...
A fuse should be placed in the...
The earth wire protects against...
If a fault makes the case live, the earth wire gives the current a safe path and the fuse blows.
The fuse and switch go in the live wire, so the appliance is cut off from the supply when they break. The earth wire (green and yellow) connects the metal case to earth, so a fault current flows safely away and blows the fuse.
Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.
A fault connects the live wire to the metal case of an appliance. With the case earthed, a large current flows and...
An appliance normally draws a current of 3.0 A. The most suitable fuse from those available is...
A plastic-cased appliance is double insulated. It does not need an earth wire because...
The mains circuit completes the electrical safety strand. Keep the chain going.