Bussmann FRS-R-100 Fusetron Energy Efficient Fuse

The Bussmann FRS-R-100 Fusetron energy-efficient fuse is a Class RK5 dual-element, time-delay cartridge fuse rated for 100 A and up to 600 V AC (600 VAC) and 300 V DC. It delivers current-limiting protection with an interrupting rating of 200 kA at 600 VAC, enabling rapid clearance of high fault currents in power circuits. As part of the energy-efficient Fusetron line, it is marketed to save energy in protected systems—about 23% more efficient than standard RK5 fuses in typical usage—while preserving time-delay performance for circuits with inrush, such as motors, transformers, and power supplies. The FRS-R series uses dual-element construction for improved safety and selective coordination within equipment, and the 10-second minimum short-time rating at 500% of rated current provides a defined tolerance for short-term overload events.