Chapter 5

• Where is the Main supplycome from

  The electricity that comes from the national grid, which is an alternating current of 230 volts at 50 hertz
• Three core cable


  • Contains a live wire, a neutral wire, and an earth wire
• Live wire


  Brown wire that provides the alternating potential difference of around 230 volts from the main supply
• Neutral wire


  Blue wire that acts to complete the circuit by carrying away current
• Earth wire

  Striped green and yellow wire that doesn't normally carry a current and has a potential difference of zero volts, its role is to stop the appliance casing from becoming live
• Live wire at 230 volts


  Electricity passes through the neutral wire or earth wire which have a potential difference of zero volts
• What happens if you touch the live wire

  Causes a large current to flow through the person, resulting in an electric shock
• It's important to never touch plug sockets, even if they're switched off, as the live wire still has a potential difference
• Formula for power:


  power(w) = energy transferred(j)

  ------------------

  time(s)
• How does the fuse and earth wire work?

  If the current gets too high it means the temperature will also increase this will melt the fuse breaking the circuit.the earth wire has a potential difference of 0 volts so it is grounded and the current will flow through th earth wire instead of the person.
• what is the formula for power?

  Power = energy transfered