Bussmann FRS-R-300 Fuse

FRS-R-300 is a Bussmann/Fusetron time-delay fuse (class RK5) rated for 300 A in 600 VAC circuits and 300 VDC, designed as a dual-element, current-limiting protector for electrical power systems. This non-indicating, blade-body fuse features an interrupting rating of up to 200 kA at 600 VAC and 20 kA at 300 VDC, offering reliable short-circuit protection while tolerating moderate inrush and surge events. The FRS-R series, part of Eaton's Bussmann family, is known for robust performance in electrical distribution and industrial applications, with a body length of about 11-5/8 inches and a diameter of roughly 2-11/32 inches. Commonly marketed as FUSETRON and listed under part numbers like FRS-R-300, it appears in catalogs from DigiKey, Grainger, Mouser, and other distributors, confirming its suitability for 600 VAC systems and 300 VDC rating. Use cases include high-current protection in feeders, power supplies, and machinery where a time-delay fuse is needed to balance fast fault response with endurance during legitimate surge conditions.