mains electricity

What does AC mean

alternating current

what does DC mean

direct current

what type of supply is mains electricity

AC

What is meant by frequency of supply

the rate at which AC changes

what type of current do batteries and cells supply

direct current

what is the power rating of an appliance

how much energy is converted per second

what wires does a typical appliance have

live, neutral, earth

what colour is the live wire

brown

what colour is the neutral wire

blue

what colour is the earth wire

green and yellow

when does the earth wire carry a charge

normally doesn’t, current flows when a fault occurs in the appliance

what potential is the neutral wire at

0 volts

state the potential different between the live and earth wires

230 Volts

what is the purpose of the neutral wire

to complete the circuit by connecting the object back to mains supply

for metal appliances where is the earth wire connect to

connected to the metal casing of the appliance, if the live wire touches the casing the current will flow through the earth wire instead preventing harm

how does a fuse wire stop the device form getting damaged

when current is too high, fuse wire melts and breaks, stopping current from flowing through the device

why is it dangerous to have a connection between earth and live wires

can result in current surge causing electrical shocks