Impressed voltage
Impressed voltage (IV) is an umbrella term used by many in the electrical power industry to encompass the following: 1. Capacitive coupling (arising from the electric field and voltage source) 2.Inductive coupling (arising from the magnetic field and current source) 3.Conductive coupling (arising from current flow through a connection with earth) 4. Trapped charge (arising from residual charge left on the capacitance of an item of equipment). The term IV relates to the existence of a voltage on an item of equipment, or metallic object, which is not directly connected to the energised power system, but which has arisen as a result of either an electrical coupling mechanism, or a residual charge at the time of circuit de-energisation. Such voltages can be dangerously high and a source of danger and therefore must be eliminated before contact is made with the equipment/metallic object. IV is a significant safety hazard to be managed and controlled on any electrical construction site.
Impressed voltage, Page 1 of 2
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