Fuse, 20 A, 600V AC, 300V DC, Class J, LPJ-I Series, Indicating, Time Delay, Body Style Cylindrical, Nonrejection, Interrupt Rating 100kA at 300V DC, 300kA at 600V AC, Fuse Size 2-1/4 in L x 13/16 in dia, Length 2 1/4 in, Width Not Applicable, Depth Not Applicable, Diameter 13/16 in, Equivalent Brand and Series Bussmann LPJ-I, Littelfuse JTD-ID, Mersen AJT, Equivalent Series AJT, JTD-ID, LPJ-I Time-delay, indicating UL Class J fuses tolerate temporary inrush currents without opening, which prevents nuisance-blowing from motor and equipment startups. Also called slow-blow Class J fuses, they open to disconnect an electrical circuit when exposed to sustained loads and short circuits. They have a visual indicator to make it easier to identify blown fuses for replacement.UL Class J fuses have.