A low resistance wire used for safety with the fuse to help protect people from electric shocks and stop devices or appliances setting on fire
Earth wire
One end is screwed to the metal casing of an electric device, the other end is connected to a big metal spike hammered into the ground
How the electric current flows
Flows through the fuse, then into the appliance through the brown live wire, through the heating element, and leaves the appliance through the blue neutral wire back to the mains supply
Appliance has a metal casing
Needs an earth wire connected to it
Appliance is working properly
The earth wire is not actually being used
Live wire becomes loose and touches metal casing
Creates a short circuit, current flows down the earth wire, fuse blows
No earth wire present
Metal casing becomes live, risk of electric shock
Double insulation
No need for an earth wire because no metal parts are showing that could be touched by the user
