Question

A 3-pin mains plug is fitted to the cable for a 1 kW electric kettle to be used on a 250 V a.c. supply. Which of the following statement is not correct?

Options

• The fuse should be fitted in the live wire.

• A 13 A fuse is the most appropriate value to use.

• The neutral wire is coloured black.

• The green wire should be connected to the earth pin.

Answer 1

A 13 A fuse is the most appropriate value to use.

Explanation:

Given: Power (P) = 1 kW

Voltage (V) = 250 V

We know that,

P = VI

⇒ I = `P/V`

⇒ I = `1000/250`

⇒ I = 4 A

A safety fuse rating should always be slightly higher than the device's normal operating current. For a device drawing 4 A, a 5 A fuse is the most appropriate. A 13 A fuse is way too high; it would allow dangerously high current to flow without blowing, failing to protect the circuit in a fault event.