S&C Electric Company 123040R4 Fuse Refill SM-4

The S&C Electric Company 123040R4 SM-4 Fuse Refill is an expendable refill unit designed for use in SM-4 and SML-4 holders. Each package contains 25 refills (25EA) for convenient stock replenishment after a fuse operation. This refill is rated 25 kV nominal with a 27 kV maximum, and carries a 25E current rating, aligning with the SM-4 protection scheme used in metal-enclosed and outdoor distribution switchgear. In SM-4 families, the 123040R4 is part of a cross-compatible lineup that includes 253040R4, 124040R4, and 254040R4, allowing substitution across related assemblies while maintaining the same voltage class. Refill units are intended to be replaced following a fuse operation, helping minimize downtime and ensure continued protective coordination in substations. S&C SM fuses and refill units are commonly used to protect transformers, capacitor banks, and cables in outdoor distribution environments, making the 123040R4 a practical inventory choice for service crews maintaining SM-4-based switchgear.