Electrical circuits may be connected to ground (earth) for several reasons. In mains powered equipment, exposed metal parts are connected to ground to prevent user contact with dangerous voltage if electrical insulation fails. Connections to ground limit the build-up of static electricity when handling flammable products or electrostatic-sensitive devices.
In some telegraph and power transmission circuits, the earth itself can be used as one conductor of the circuit, saving the cost of installing a separate return conductor. (See single-wire earth return)

Grounding means linking an electrical circuit to the ground and works on the principal that the earth is a handy conductor of electricity. The grounding of electrical devices and appliances protects those who handle and use them from electrical shocks and accidents.