In
electricity supply systems, an
earthing system or
grounding system is circuitry which connects parts of the electric circuit with the
ground, thus defining the
electric potential of the conductors relative to the Earth's conductive surface. The choice of earthing system can affect the
safety and
electromagnetic compatibility of the power supply. In particular, it affects the magnitude and distribution of
short circuit currents through the system, and the effects it creates on equipment and people in the proximity of the circuit. If a fault within an electrical device connects a live supply conductor to an exposed conductive surface, anyone touching it while electrically connected to the earth will complete a circuit back to the earthed supply conductor and receive an
electric shock.