Eaton Bussmann 3-Pole Industrial Fuse Block, AC: 600 VAC, DC: 300 VDC, 35 to 60A, Series FRN, FRS, KTN-R, KTS-R, KWN-

These fuse blocks are compatible with UL Class RK1 and RK5 fuses. They are rejection-style blocks with clips that fit the modified terminals of Class R fuses to prevent the installation of fuses with a lower voltage rating or interrupting capacity. They're used with RK1 fuses to provide high current limitation for applications where a fast response to overcurrent is required. They're used with Class RK5 fuses to provide moderate current limitation for general use applications.

UL Class and midget fuse blocks accept fuses sized and rated according to UL Class or midget specifications. They have an open top for access to fuses, clips or studs for securing fuses within the block, and terminals for connecting to the circuit. These fuse blocks are either bolted down or mounted on a DIN rail to hold them in place. They're commonly paired with fuse box covers to enclose the fuses and prevent accidental contact. They are nonindicating, so there's no visual signal when a fuse is blown.