SMU 20 Fuses From S&C Electric

Although it looks and handles like a cutout, the SMD-20 is a power fuse, offering the full fault-spectrum protection of all S&C Power Fuses. It is ideally suited for protection of transformers, lines, cables, and capacitors located on outdoor distribution feeders or in distribution substations where the higher fault currents, higher voltages, and higher loads encountered on today's systems may push cutouts beyond their capabilities. These solid-material power fuses provide unique low-arc-energy fault interruption with a mild exhaust-so they're much quieter operating than conventional distribution cutouts or horn-fiber power fuses.

SMD-20 Power Fuses consist of two basic components- a complete mounting and a replaceable SMU-20 Fuse Unit. The mounting includes the base (or mounting bracket in the case of overhead-pole-top style mountings), insulator(s), latch-and-upper-contact assembly, hinge-and-lower-contact assembly, and reusable upper and lower fuse-unit end fittings. Fuse-unit end fittings are available separately to enable users to equip spare SMU-20 Fuse Units for quick replacement when re-fusing.

Features of SMU 20 & SMU 40 Fuses From S&C Electric

  • Precision-engineered nondamageable silver or pretensioned nickel-chrome fusible elements
  • Provide precise and permanently accurate time-current characteristics
  • Permit upstream protective devices to be set for faster operation
  • Available in a wide variety of ampere ratings, and in four different speeds, i.e., "K",  Standard, Slow, and Very Slow.

Applications of SMU 20 and SMU 40 Fuses from S&C ELECTRIC

  • Transformers
  • Lines
  • Cables
  • Capacitors


  • Fuse Unit: The SMU-20 and SMU-40 Fuse Unit consists of a fusible element, an arcing rod, and a solid-material arc-extinguishing medium contained within a filament-wound glass-epoxy tube.


  • S&C Electric

Data Sheet:

  • Data Sheet 4: SMU 20 Fuses