Mains Electricity

Question 1

Colour of each wire.

Answer 1

Brown = live
Blue = neutral
green and yellow = earth

Question 2

Function of the brown wire.

Answer 2

Carries the 230 V alternating potential difference from the power supply.

Question 3

Function of the blue wire

Answer 3

Completes the circuit from the appliance back to the supply.

Question 4

Function of the earth wire

Answer 4

This is at 0 V and does not form part of the normal circuit. It is there for safety.

Question 5

What is wrong with a plug that has no fuse?

Answer 5

There will be a constant surge which can result in a fire.

Question 6

Why do some appliances not have an earth wire.

Answer 6

Made of plastic or has plastic casing.

Question 7

Why do we get electric shocks from touching the live wire?

Answer 7

We touch the ground, the ground has 0V, the live wire is 230V which means the P.D is large enough to push the current through you.

Question 8

Explain how the earth wire and fuse work together to protect humans from faulty appliances?

Answer 8

The earth wire redirects the current safely, while the fuse cuts off the power.

Question 9

What does a fuse box contain and why is that better than fuses?

Answer 9

It contains Circuit breakers. Reusable, Faster response and they are more precise.