Mains electricity

What type of current is mains electricity

Alternating current (flow of electrons moves in the forward and then reverse directions)

What is the mains supply frequency and potential difference

50Hz

230V

How are electrical appliances in the Uk connected to the mains supply

Through a 3 core cable

3 types of wire

Live

Neutral

Earth

What are the wires made out of

Copper, which is a good conductor

What covers the wires

Coatings are made of plastic which does not conduct electricity

Function of live wire and colour

Brown

Carries potential difference from supply

P.d=230V

Function and colour of neutral wire

Blue

Completed the circuit

P.D=0

Coloir and function of earth wire

Green/yellow striped

Safety wire and carries current if there’s a fault to stop the appliance becoming live

P.D=230V

Risk of live wire

It is extremely dangerous and could be fatal if touched

Why are appliances with a metal case dangerous

If the live wire comes loose and touches the metal case the case can become live and fatally electrocute you

How does the earth wire save us from the metal case

The earth wire is connected into the ground with a metal rod. If the case becomes live a huge current flows to the earth. The fuse melts and shuts off the current