Mersen Amp-Trap fuses for the protection of transformers and distribution lines deliver overload and short circuit protection. These general purpose 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 are single, double or triple barrels 3 inch diameter (size D) and mount in unique cam-locking clips for superior connections as well as easy installation and replacement. 5500 Volts 400 amps D0R0 series.