Fuses and Earthing

Question 1

In which wire of an appliance should a fuse be connected?

Answer 1

The live wire

Question 2

Give the name of a device that can be used in a place of a household fuse.

Answer 2

Circuit breaker

Question 3

True or false? In an electrical appliance, the fuse should be rated just lower than the normal operating current.

Answer 3

False

The fuse should be rated just higher than the normal operating current.

Question 4

Give one risk of too large a current flowing in an appliance.

Answer 4

The wiring in the appliance could melt / cause a fire

Question 5

What is the purpose of the earth wire in an appliance?

Answer 5

It stops the appliance becoming live if a fault develops in which the live wire touches the appliance’s metal case. This keeps users of the appliance safe from getting an electric shock.

Question 6

Explain how a fuse works to minimise the risks to an appliance if there is a surge in current.

Answer 6

If there is a surge in current, the fuse melts, breaking the circuit and cutting off the live supply. This prevents the currents surge flowing through the appliance and so minimises the risk of fire from the heating effect of the current