Earthing is used to protect you from an electric shock. It does this by providing a path for a fault current to flow to earth. It also causes the protective device (either a circuit-breaker or fuse) to switch off the electric current to the circuit that has the fault.
There are three main purposes for earthling:
System earthing
System earthling serves a purpose of electrical safety throughout the system that is not caused by an electrical fault. Its main purpose is to prevent static buildup and to protect against power surges caused by nearby lightning strikes or switchingSystem earthing
Equipment earthing
Equipment earthing serves a purpose of electrical safety in an electrical fault. Its main purpose is to prevent equipment damage and the risk of an electric shock.
Functional earthing
Functional earthing serves a purpose other than electrical safety.
