fusing current
                  Fusing factor   =     -------------------
                                                   current rating
Rewritable fuses fusing factor  approximately 1.8 to 2.
Cartridge fuses fusing factor between 1.25 & 1.75
HBC fuses fusing factor up to 1.25 (maximum)
Circuit breakers are designed to operate at no more than 1.45 times their rating.