Mains Electricity: safety

Posted in AQA GCSE P2, P2: Mains Electricity by Mr A on 1 Mar 2010


  • Electricity is dangerous!
  • Structure of cables
  • Fuses
  • Earth wire
  • Three-pin plugs



Electricity is dangerous!

An electric shock can affect your muscles and nerves; it can paralyse you or stop your heart beating. You can get an electric shock from anything plugged in to the mains.



Structure of cables




Wires are coated in plastic for safety. The metal wires allow a current to flow as they conduct electricity. The plastic coating is an insulator which prevents people from being electrocuted.





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Earth wire


The most dangerous thing that can go wrong with an appliance is that the live wire becomes loose inside and touches the casing. If the casing is metal it will become live. If you touch the casing, you will get an electric shock.


The earth wire is connected to the inside of the casing. Then, if the live wire touches the casing, charge will flow through the earth wire (rather than you), and the fuse will blow.





Three-pin plugs



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