S&C Power Fuses for Transmission Protect Utility & Industrial Substations

S&C 38kV-138kV SMD Power Fuses for Outdoor Transformers and Capacitor Banks

S&C SMD Substation Transformer Fuse

S&C SMD Substation Transformer fuses provide system protection as well as protecting transformer and capacitor banks

SMD‑1A, SMD‑2B, SMD‑2C, SMD‑3, SMD‑50


Power fuses for outdoor substations are like overdraft protection from your bank. In this case, outdoor substation transformers and capacitor banks are the bank, and SMD Fuses for Transformer and Capacitor Banks keep the transmission system protected and balanced when (power current overload) overdraws occur.

S&C SMD Power fuses provide system protection as well as protecting transformer and capacitor banks. The fuse operates promptly to minimize short-circuit stresses on source side conductors and equipment and also limit the extent of service interruption to the smallest possible portion of the system.

Overloads are like bouncing a check, and S&C SMD power fuses respond to overdraws accordingly

S&C SMD Power Fuses

Fuse Types SMD‑1A, SMD‑2B, SMD‑2C, SMD‑3, and SMD‑50 provide dependable,

SMD Fuses in an Outdoor Substation

SMD Fuses in an Outdoor Substation

economical circuit protection in outdoor substations 34.5 kV – 138 kV.  They are offered with maximum continuous current ratings from 100A to 300A (depending on fuses type and voltage rating), and are available with fault-interrupting ratings as summarized in the tables on pages 18 & 19 in the brochure listed in this article for download.



Slow or Fast Power Fuses? Timing is Everything

SMD Fuse units for outdoor power transformers and capacitor banks are available in a wide range of ampere ratings and in three different speeds: slow, very slow, standard and fast acting. Timing refers to fuse tolerance before it blows. SMD fuses have 10% tolerance, compared to 20% with many other fuses. Transformers (and motors) “inrush” currents during startup need a built-in time delay with precise tolerance to handle fluctuating currents.


An Element of Reliability

SMD Power Fuses incorporate non-damageable silver or nickel-chrome fusible elements. This precision element delivers precise time-current characteristics. This assures system reliability through better coordination with other fuses and equipment.

SMD power fuses can be set for faster operation than might be recommended with other power fuses or circuit breakers without affecting system coordination.


Transformer Protection with S&C SM Power Fuses

SMD Power Fuses with their unique solid-material construction provide full-fault

SMD Outdoor Transmission 38-138kV - with SMD-1A mounting assembly

SMD Outdoor Transmission 38-138kV  SMD-1A mounting assembly with fuse.

spectrum protection capable of detecting and interrupting all faults. Whether the fault is on the primary or secondary side, with line to line or line to ground voltage across the fuse; whether the transformer is adjacent to the fuse or cable connected to it remotely and regardless of the transformer winding connections.

In addition, the construction prevents the fuse elements from damage caused by transient surges and can withstand transformer magnetizing-inrush currents as well as hot- and cold-load pickup currents assuring maximum protection for your transformer.


Capacitor Bank Protection with Type SMD Power Fuses

Along with transformer and cable protection, SMD Power Fuses are suitable for fusing of station capacitor banks, particularly where available fault currents are high. SMD power fuses can endure significant continuous peak-loads, allowing for smaller ampere ratings without risking nuisance fuse operations. Close fusing with SMD Power Fuses ensures rapid isolation of faulted capacitor banks, thereby protecting the system form unnecessary outages.

SMD Power Fuse Characteristics

  • Nickel-chrome current-responsive elements and solderless construction for melting time in close coordination with upstream and downstream devices
  • 10% total tolerance in melting current, compared to the 20% tolerance of many fuses
  • Fusable close to transformer under full load for protection against broad range of secondary side faults
  • Melting time adjustable for faster operation and closer coordination with other protective devices
  • Available in standard, slow and very slow speeds
  • Broad amperage ratings for fusing close to the power source for additional protection and coordination


Fuse Selection & Sizing for Transformers and Capacitor Banks

Power distribution transformers handle a wide range of currents. You can avoid fuse sizing mistakes when selecting and correctly sizing replacement fuses for power distribution transformers. Proper fuse selection depends on many factors, so consult a professional engineer for your application


S&C Power Fuses Types SMD-1A, SMD-2B, SMD-2C, SMD-3, and SMD-50

Monster Fuses is a Factory Authorized
Provider of S&C Power Fuses and Hardware, and all major fuse lines.


Monster Electrical is a “knowledge-based” independent distributor of fuses, fuse hardware and control equipment. We don’t just ship boxes. Our product and application knowledge goes into every transaction.

Monster Fuses provides immediate shipment of power fuses and power fuse mountings from our extensive inventory. Clients can access more than 14,000 power fuse solutions provided from a stock of 100,000+ fuses, eliminate long factory power fuse lead times, and supply real time solutions for urgent fuse challenges in utility, industrial, institutional and commercial applications.

Monster Controls provides immediate shipment of 5kV Class control components. Clients can access thousands of 5kV class control parts from an extensive inventory, eliminate long factory lead times and supply real time solutions for electrical control challenges. Specializing in parts for 2.3kV, 5.5kV and 7.2kV motor starters, contactors and switches, Monster Controls also stocks complete starters, contactors and switches.

Need help calculating fuse current ratings for transformers or selecting fuse hardware, power equipment and electrical replacement parts? Call 888-444-4335 in the West or 877-444-1798 in the EAST.


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