What is the purpose of grounding (an electrical ground) in a circuit or appliance?

GROUNDING provides a SAFE PATH for electrical current to flow into the EARTH if a fault occurs — protecting people from electric SHOCK. ASVAB Electronics Information tests safety. If a fault causes the metal case of an appliance to become 'live,' the ground wire safely carries that current to earth (rather than through a person who touches it), and typically trips a breaker or blows a fuse. The third (round) prong on a plug is the ground connection. Grounding is a critical safety feature. Knowing grounding protects against shock by providing a safe path to earth is commonly tested.