mains electricity

• Three core cable


  Cable used to connect appliances to mains electricity, has three wires
• Wires in three core cable

  • Live wire
  • Neutral wire
  • Earth wire
• Live wire


  Carries potential difference of around 230 volts, connected to fuse in plug
• Neutral wire


  Completes the circuit with live wire, has potential difference of around 0 volts
• Earth wire


  Safety wire, connected to metal case of appliances to prevent electric shock
• How appliances are connected to mains electricity

  1. Live wire carries 230V electricity

  2. Live wire connected to fuse

  3. Neutral wire completes circuit

  4. Earth wire provides safety connection
• Mains electricity in UK is alternating current (AC) with frequency of 50 Hertz and potential difference of around 230 volts
• If live wire comes loose in appliance with metal case

  Metal case can become live, posing risk of electric shock
• How earth wire prevents electric shock

  1. Earth wire connected to metal case

  2. If case becomes live, large current flows to earth

  3. Fuse melts, shutting off current