Plugs and cables: Electricity: Physics: GCSE (9:1)

• Electrical conductor

  A material with a low resistance that allows an electric current to pass through it easily

  
• Electrical insulator


  A material with a high resistance that does not allow an electric current to pass through it easily

  
• Plug (three pin)

  Connects an electrical appliance to the mains electricity supply

  
• Cable (three core)

  The cable between the device and the plug which contains three copper wires coated in plastic

  
• Reason why is copper used for wires

  Copper is a good electrical conductor
• Reason why is plastic is used to cover wires

  Plastic is a good electrical insulator
• Cable grip


  Holds the cable in place so that the wires inside do not become loose

  
• Outer insulation

  Extra plastic insulation wrapped around the inner wires in a three-core cable

  
• Fuse


  A safety device found in a plug that contains a thin wire which melts if too much current flows

  
• Live wire


  A wire coated with brown plastic that carries the alternating potential difference from the supply

  
• Neutral wire


  A wire coated with blue plastic that completes the circuit

  
• Earth wire


  A safety wire coated with green and yellow striped plastic to stop the appliance becoming live

  
• The potential difference between the live wire and earth

  230 V
• The pd of the earth wire

  0 V (unless there is a fault with the appliance)
• The pd of the neutral wire

  At (or close to) 0 V
• Reason the earth wire carries a current

  If there is a fault with the appliance