GFCI (Ground Fault Circuit Interrupters)

A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds some predetermined value that is less than that required to operate the overcurrent protective device of the supply circuit.

Ground or Earth

The reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the Earth.

Inductance (H)

The property of a conductor by which a change in current flowing through it induces (creates) a voltage (electromotive force) in both the conductor itself (self-inductance) and in any nearby conductors (mutual inductance). Measured in henry (H).

Kilowatt-hour (kWh)

The product of power in kW and time in hours. Equal to 1000 Watt-hours. For example, if a 100W light bulb is used for 4 hours, 0.4kWhs of energy will be used (100W x 1kW / 1000 Watts x 4 hours). Electrical energy is sold in units of kWh.


Anything which consumes electrical energy, such as lights, transformers, heaters and electric motors.


a body which has the property of at. tracting iron or other magnets. its molecules are aligned.

Magnetic Field

that area near a magnet in which its property of magnetism can be detected. it is shown by magnetic lines of force.