Electrical Definitions


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Electrical Definitions

Letter - O


The derived unit for electrical resistance or impedance; one ohm equals one volt per ampere. The unit of electrical resistance. Represented by R.



An instrument for measuring resistance in ohms.



An electronic device for converting dc energy into ac energy.



A point on the wiring system at which current is taken to supply utilization equipment.


Outline Lighting

An arrangement of incandescent lamps or electric-discharge lighting to outline or call attention to certain features such as the shape of a building or the decoration of a window.



Any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload, short circuit, or ground fault.



Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that, when it persists for a sufficient length of time, would cause damage or dangerous overheating. A fault, such as a short circuit or ground fault, is not an overload.