The pulse factor is determined by the fuse element construction, materials, cross sectional area, and the number of surge pulses that can withstand. The task of a circuit designer is to select a fuse with the minimum I²t value, but greater than the energy of an inrush current. This rating ensures that the fuse will not cause a nuisance opening during transient conditions. The I²t Fuse parameter can be found in fuse datasheets. Do not use the fuse’s maximum melting integral in the equation presented here. Instead, use either the minimum or nominal melting integral of the fuse.