S&C Electric Company 123100R4 SM-4 Fuse Refill

123100R4 SM-4 fuse refill is a replacement fuse element for S&C SM-4 power fuse holders, delivering a 65E (65 A) rating with a nominal voltage of 25 kV and a maximum of 27 kV. This refill unit is designed for use in SM-4 and SML-4 holders and is also compatible with SME-4Z holders. In the SM-4 refill family, 123100R4 represents the 65E/25 kV option, with related refills such as 253100R4; higher-voltage variants include 124100R4 and 254100R4 (34.5 kV nominal, 38 kV max). These refill units replace spent fuse elements in outdoor distribution substations to protect feeders, transformers, and capacitor banks without replacing the entire holder.