domestic uses and safety

what is direct voltage

current always flowing in the same direction

what is alternating voltage

current constantly changing direction

What is the UK mains supply?

230V

function of neutral wire

Completes the circuit

- blue

function of live wire

Provides the alternating potential difference from the mains supply

brown

function of earth wire

A safety wire to stop the appliance becoming live

green and yellow

what is the potential difference between the live wire and the earth wire

0V

how is a live wire dangerous even if a plug is turned off

there is still a potential difference

if you made contact with the live wire your body would provide a link between the supply and the earth, so a current would flow through you