mains electricity

• direct pd = direct current (only moves in 1 direction) which doesn't go below 0

  e.g. batteries
• alternating pd = ac (moves backwards and forwards) which goes below 0

  eg mains electricity
• main electricity

  frequency = 50 hz

  pd = 230 V
• most electrical appliances are counted to mains by a 3 core cable, of which insulation for each is coded

  LIVE = BROWN

  NEUTRAL = BLUE

  EARTH = YELLOW/GREEN
• LIVE = BROWN

  carries the alternating pd from supply

  pd between wire and earth is 230 V

  can be dangerous when a circuit is open as when touched a person could complete the circuit to ground themselves= electrocuted as a current will flow through them
• any connection between a live wire and earth can cause a current to flow:

  • electrical fires if current is too high
  • electrocution is person makes a connection
• FUSE: connected to live wire and has a maximum current rating, if this is exceeded , it breaks the circuit since it heats up and melts
• NEUTRAL = BLUE

  completes the circuit

  is close to or at 0V
• EARTH = YELLOW/GREEN

  safety wire that stops the appliance from becoming live

  0V, only carries a current if there is a fault