mains electricity

• What type of current is mains electricity in the UK?

  Alternating current (AC)
• What is the frequency of alternating current in the UK?

  50 hertz
• What is the potential difference of mains electricity in the UK?

  230 volts
• How are electrical appliances connected to mains electricity?

  Using three core cable
• What material are the wires in a three core cable made of?

  Copper
• What is the purpose of the plastic coating on the wires?

  It prevents electrical conduction
• What are the three wires in a three core cable?

  • Live wire (brown)
  • Neutral wire (blue)
  • Earth wire (green and yellow striped)
• What does the live wire do?

  It carries a potential difference from the supply
• What is the potential difference of the live wire?

  230 volts
• What is the function of the neutral wire?

  It completes the circuit with the live wire
• What is the potential difference of the neutral wire?

  0 volts
• What is the purpose of the earth wire?

  It acts as a safety wire
• Why can the live wire be dangerous even when the switch is open?

  It still has a potential difference of 230 volts
• What happens if someone touches the live wire?

  A current flows through them into the Earth
• Why are appliances with metal cases dangerous?

  If the live wire touches the case, it becomes live
• How does the earth wire protect against electric shock?

  It directs current to the ground if live
• What happens when the metal case becomes live?

  A huge current flows to the Earth
• What is the role of the fuse in the plug?

  It melts and shuts off the current