Half Cycle of Current - A half loop of current having a duration of 0.00833 seconds.
Half Loop of current - The amount of time it takes the current to go from one zero reference to another.
Harmonic - Sinusoidal component of an arc voltage that is a multiple of the fundamental wave frequency.
Harmonic Distortion - The presence of harmonics that change an ac voltage waveform from sinusoidal to complex.
Heat Run Test - A test used to determine the temperature rise of a device under rated load.
Heavy Duty - A lightning impulse classifying current category for distribution class arresters defined by ANSI/IEEE C62.11. A heavy duty rated arrester has a 10,000 amperage impulse value crest (refer to normal duty).
Hertz (Hz) - Expression of ac frequency in cycles per second, e.g., 60 Hz.
High-amp ELSP - CPS's three inch diameter, 125-200 A, ELSP Fuses.
High Voltage and Low Voltage Windings - Terms used to distinguish the winding having the greater voltage rating from that having the lesser in two-winding transformers. The terminations on the high voltage windings are identified by H1, H2, etc., and on the low voltage by X1, X2, etc.
HV - High voltage.