This Standard specifies essential safety requirements for semi-enclosed electric fuses, with current ratings up to, and including, 100 A, intended for installation as protective devices required under AS 3000 and intended for use in 50 Hz a.c. circuits with voltages not exceeding 650 V.In general, these fuses are used to protect circuits having a prospective fault current up to 4 kA. Household installations usually come within this category.NOTE: At currents smaller than rated minimum fusing current, the fuses do not give protection, because they do not blow, or blow only after an indeterminately long time. They may, however, deteriorate if they continuously carry currents greater than rated current.