Mersen's surge suppression fuses are specially designed to address the protection of Surge Protective Devices (SPD). The surge suppression fuses have been specially designed to withstand 8x20 MicroSec surge pulses without opening, allowing the SPD to react to the surge. All surge suppression fuses have a 8x20 MicroSec surge rating, not a continuous current rating. Under AC short circuit conditions these surge suppression fuses are very current-limiting. 600 Volts 30 surge capacity ferrule mounting.