Domestic uses and safety

• what type of supply is mains electricity

  alternating current
• frequency of mains electricity

  50 Hz
• voltage of mains electricity

  230 v
• features of alternating current

  current continuously varies , from positive to negative (charge changes direction)
• features of direct current

  movement of charge in one direction
• what current do cells and batteries supply

  direct current
• colour of the live wire

  brown
• what does the live wire do

  carries alternating potential difference from supply
• why can the live wire be dangerous

  if main circuit is cut off, current may still be flowing through it
• colour of the neutral wire

  blue
• voltage of live wire

  230 v
• voltage of neutral wire

  0 v
• what does the neutral wire do

  completes the circuit
• colour of the earth wire

  green and yellow stripes
• voltage of earth wire

  0 v
• what does the earth wire do

  only carries a current if there is a fault - safety wire to stop appliance becoming live
• how does the earth wire work

  connected to earth and casing , if live wire touches metal casing of appliance , it'll become live