Earthing is the first step towards electrical safety. The body of electrical equipments, applinaces etc is to be connected to earth for safe discharge of electric current to the earth, in the event of any leakage , fault etc.
The earth is considered to be zero potential. Earthing is done to provide safety to user from electric shock.
It is a set of conductors connected in series or in parallel in order to dissipate the potential difference immediately into the ground.
The wire connected from equipment to earth called earthing wire.
The resistance of earthing wire is low value to provide least resistance path for leakage of fault current.
The area of cross section of conductor is more as resistance is inversely proportional to area of cross section. That is why size of earthing wire is always more.
All metallic part of wiring system must be earthed using one continuous earthing wire in the form of bare copper wire/strip throughout the wiring circuit.
There should be any joints in the earth wire.