Mersen surge suppression fuses are specially designed to address the protection of SPD systems. Our surge suppression fuses have been specially designed to withstand 8/20 µSec surge pulses without opening, allowing the SPD system to react to the surge. All surge suppression fuses have a 8/20 µSec surge rating, not a continuous current rating. Under AC short circuit conditions these surge suppression fuses are very current limiting.