Plugs and wires

• What is the main source of electricity in the UK?

  The national grid
• What type of current is supplied by the national grid in the UK?

  Alternating current
• What is the voltage of the main supply in the UK?

  230 volts
• What is the frequency of the electricity supplied in the UK?

  50 hertz
• What does plugging an electrical appliance into a socket connect it to?

  The main supply
• How many wires are typically found in a three core cable?

  Three wires
• What are the names of the three wires in a three core cable?

  Live wire, neutral wire, earth wire
• What material are the wires in plugs and cables made of?

  Copper
• Why are the wires coated in insulating plastic?

  For safety
• What color is the live wire?


  Brown
• What is the function of the live wire?


  To provide the alternating potential difference from the main supply
• What color is the neutral wire?


  Blue
• What does the neutral wire do?


  It completes the circuit by carrying away current
• What color is the earth wire?

  Striped green and yellow
• What is the role of the earth wire?

  To stop the appliance casing from becoming live
• Why does the earth wire not normally carry a current?


  It has a potential difference of zero volts
• What happens if the live wire touches the appliance casing?

  The casing could become live, causing an electric shock
• How does the earth wire prevent electric shocks?

  It provides an alternative pathway for the current to flow away
• Why is there a potential difference between the live wire and the neutral wire?

  Because the live wire is at 230 volts while the neutral wire is at zero volts
• What happens if a person touches the live wire?

  It causes a large current to flow through them, resulting in an electric shock
• Why is it dangerous to touch plug sockets even when switched off?

  The live wire still has a potential difference
• What are the key components of a three core cable and their functions?


  • Live wire (brown): Provides alternating potential difference of 230 volts
  • Neutral wire (blue): Completes the circuit by carrying away current
  • Earth wire (striped green and yellow): Prevents appliance casing from becoming live
• What are the potential differences of the live, neutral, and earth wires?

  • Live wire: 230 volts
  • Neutral wire: 0 volts
  • Earth wire: 0 volts
• What safety measures are in place to prevent electric shocks from appliances?


  • Insulating plastic coating on wires
  • Earth wire providing an alternative pathway
  • Proper identification of wire colors