Plugs sockets cables and short circuits

Explain why each of the wires in a three-core mains cable is insulated.

• To keep them warm

• To keep them cool

• To prevent electrical connection between them inside the cable

The fuse in a circuit melts when:

• An appliance isn't earthed
• Too much current flows
• Too much voltage flows

What's the first thing you should do if someone is shocked electrically?

• Use the fire extinguisher
• Check for breathing and heartbeat
• Turn off the power source
• Remove the person from the power source

Electric current moves in only one direction. 

• True
• False

Explain why the cables joining the wall sockets in a house need to be thicker than the cables joining the light fittings. Pick 2.

• Sometimes the appliances plugged in might draw more current than light fittings.

• Light fittings always need more current than appliances that are plugged in.

• When more current is needed thicker cables are required in order to lower the resistance and reduce power loss and heating.

• When more current is needed thinner cables are required so the current goes faster

• When less current is needed thicker cables are required to make sure they stay cool.

Describe the difference between a 2-core cable and a 3-core cable. Pick

• 2-core has only got yellow/green and blue

• 2-core has only got brown and blue

• 2-core contains the neutral wire and the live wire.

• 2-core contains the earth and the live wire.

Explain what determines whether an appliance should have a 2-core or a 3-core cable.

• What the electrician has left when she is wiring the plug.

• How much power the appliance uses.

• Whether the appliance is likely to be touched by someone.

• Whether the appliance has a metal case.

What colour is the live wire in a mains plug?

• Green
• Blue
• Brown

This is the circuit symbol of a

• resistor

• battery

• fuse

• switch

• an earth wire

If a bulb uses 10A, which fuse would be best?

• 10A

• 13A

• 8A

• 5A