How does the grounding wire in an A.C. circuit protect against electrical shock?
P.L., via e-mail Coming in contact with a hot wire while standing on a grounded, conductive surface will allow your body to become a parallel return conductor to ground and result in you experiencing an electrical shock. The ground wire provides the current with an alternative low-resistance return path to ground. The accompanying illustration explains how this works. In the first diagram we have an A.C. motor hooked up to a two-wire system: hot (black insulation) and neutral (white insulation). Both wires are supposed to be isolated from one another as well as from the metal case of the motor. However, let’s assume that the hot wire’s insulation has failed and so the conductor is in contact with the metal motor casing. The motor will continue to operate normally, but since the casing is “hot,” coming in contact with it will produce the same result as touching the wire itself. In the second diagram, a ground wire (green insulation) is connected to the neutral wire at the power source a
