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Science

Mains electricity

Earthing

You should understand why electrical appliances are earthed.

Earthing

close up of the cooker shows the live, neutral and earth wires going into the mains, and an extra wire coming from the earth socket connecting to the casing

Earthing of an electric cooker

Many electrical appliances have metal cases, including cookers, washing machines and refrigerators. The earth wire creates a safe route for the current to flow through if the live wire touches the casing.

You will get an electric shock if the live wire inside an appliance, such as a cooker, comes loose and touches the metal casing. However, the earth terminal is connected to the metal casing so that the current goes through the earth wire instead of causing an electric shock. A strong current surges through the earth wire because it has a very low resistance. This breaks the fuse and disconnects the appliance.

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