There are two types of grounds for the ground wire, namely the system ground and the protective ground. The task of system grounding is to establish a zero potential reference point; the task of protective grounding is to protect personal safety. For protective earthing, its tasks are:
A) Provide a low-impedance connection between the equipment and the grounding body, thereby also reducing the risk of personal electric shock injury;
B) Provide a low-impedance path back to the mains for ground-fault current to operate a fuse or circuit breaker.