Answers to GCSE Mains Electricity

Practice Questions

1.Describe the difference between two core and three core wire

Two core wire contains only live and neutral wires. It is used for double insulated appliances, with a plastic case. 

Three core wire contains live, neutral and earth wires. It is used for metal cased appliances.

2. State the colours of the following wires:

Live – carries the alternating potential difference from the supply to the appliance.

Neutral – completes the circuit. The neutral wire is at 0V, or near to 0V.

Earth – is at 0V, a current only flows along the Earth wire if the appliance is faulty.

3. Explain why both the live and neutral wire is needed for an  electrical appliance to work. 

The live wire brings alternating potential differece from the power source to the appliance. The neutral wire completes the circuit by providing a path for the electricity to return to the power source.

4. State the function of the cable grip in the plug.

Holds the cable in place to prevent the wire being accidently pulled out of the plug.