Terminology

DC Breakdown Voltage
     With a rate of rise of 100V/s or less, the minimum rising DC voltage that will cause Breakdown when applied across the terminals of an arrester.

Impulse Breakdown Voltage
     The maximum voltage attained by an impulse of designated waveform (100 V/µs or 1 kV/µs) applied across the terminals of an arrester prior to the flow of discharge current.

Insulation Resistance
     The resistance measured between the terminals of an arrester when the specified DC voltage is applied at a nominal ambient temperature (25°C) and relative humidity (75%).

Capacitance
     The capacitance as measured between the terminals of an arrester.

DC Holdover Voltage
     The maximum DC Voltage across the terminals of an arrester under which it may be expected to clear and return to its high impedance state after the passage of a surge under specified circuit conditions.

Impulse Life
     The minimum number of impulses of a specified waveform and peak current which an arrester will conduct without suffering any of the failure modes defined below.

Impulse Discharge Current
     The maximum current of a waveform of 8/20µs that can be applied across the terminals of an arrester without causing the arrester to fail as defined by the failure modes described below.

AC Discharge Current
     The RMS current value that an arrester will conduct without suffering any of the failure modes defined below when a current of 50 Hz or 60 Hz is applied for a period of 9 cycles (50 Hz) or 11 cycles (60 Hz).

Failure Judgment
     After the Impulse Life Test, Impulse Discharge Current Test and the AC Discharge Current Test, an arrester shall be judged to have failed if any of the following failure modes exists.

Low DC Breakdown Voltage
     Less than 50% of the nominal DC Breakdown Voltage

High DC Breakdown Voltage
     More than 150% of the nominal DC Breakdown Voltage

High Impulse Breakdown Voltage
     More than 150% of the nominal 100V/µs Impulse Breakdown Voltage

Insulation Resistance
     Less than one Megohm