Lecture
A break in the grounding wire, unlike a break in a phase wire, does not cause any disruption in the operation of the appliance and can be detected either during a preventive inspection or repair, or, in the event of insulation damage and a short to the casing, after one of the workers has received an electric shock. If the broken grounding wire touches one of the live wires, a serious hazard arises, since in this case phase voltage appears on the casing of the appliance. The appearance of phase voltage may result from an error made when installing the plug or the mains socket, if the grounding wire is connected to a live contact. Such errors are possible when plugs and sockets are repaired by unqualified workers.
The appearance of phase voltage on the casing of an appliance or apparatus is also caused by a break in the grounding wire inside the mains cord and its contact with live wires. In this case the danger of electric shock is even greater, since the product continues to function normally and the fault is not immediately detected.
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