Question

How is earthing wire used?

Answer 1

it fonnects theplug to the ground preventing from electric current

Answer 2

It's a safety wire which is kept at 0 potential. It is used in the circuit for appliances which is made up of metal or they have metallic body. When there is a overload or a short circuit the excess electricity in the appliance is sucked up by the earth wire,as it provides a zero potential path for electric current to flow to the earth.