A high current of short duration that generally occurs when the power is first applied to inductive loads. The surge generally lasts no more than several ac cycles.
ANSI/IEEE C62.41.2-2002 provides test waveform recommendations for evaluating surge suppressors. Test waveform is (8 x 20 micro-seconds) 8 milli-seconds rise time and 20 micro-seconds from rise time start to 50% of fall (decay) time applied as a current wave into a short circuit.
A current of short duration that occurs when power is first applied to capacitive loads or temperature dependent resistive loads such as tungsten or molybdenum heaters-usually lasting no more than several cycles.