Domestic Uses and Safety - Paper 1

Question 1

Outline domestic electricity supply in the United Kingdom.

Answer 1

In the United Kingdom the domestic electricity supply has a frequency of 50 Hz and is about 230 V.

Question 2

Outline the colour of the insulation and purpose of each wire in the United Kingdom’s 3-core cable.

Answer 2

• The live wire (brown) carries the alternating potential difference from the supply.
• The neutral (blue) wire completes the circuit, remaining near 0V.
• The earth wire (green and yellow stripes) is a safety wire to stop the appliance becoming live, only carrying a current in a fault.

Question 3

Outline the hazards of the United Kingdom’s 3-core cable.

Answer 3

The live wire may become dangerous even if the mains circuit is not complete.
Providing a connection between the live and earth wire will short the circuit, potentially causing fire and electric shock.