Mersen fuses for the protection of transformers and distribution lines deliver overload and short circuit protection. These current-limiting fuses will melt at current that can be as low as 1.7 times the fuse current ratings up to its maximum interrupting rating. These fuses are designed to withstand the transformer magnetizing inrush current. They have 2" (size C), 3" (size D) and 2x3" (size DD) inch diameter barrels with ferrules and are mounted in spring reinforced clips. 5500 Volts 400 Amps FCB series.