Limit Amp style bolt-in R-rated Motor Starter Fuses are current-limiting, high interrupting rating fuses intended for the short-circuit protection of medium voltage motors and motor controllers. R-rated fuses are back up fuses that have a minimum interrupting rating, and must be coordinated with overload relays in combination motor starters. Elements of these fuses are designed to withstand the cyclic motor-starting application. The motor starter manufacturer generally specifies the R-rated fuse size. Most are UL Recognized.


• 2.75KV, 5.5KV, and 8.25KV. Single, Double and Four Barrel Bolt-in style

• For indoor use in or for use in a weatherproof enclosure.

• Indicator to trip auxiliary devices.

• Interrupting ratings of 65,000 amps for 2.75/5.5KV and 50,000 amps for 8.25KV fuses.


• Short circuit protection of medium voltage motors and motor controllers.



fusesPotential Transformer fuses are applied wherever it is necessary to limit the short-circuit currents on high capacity systems.


• Quiet Safe Operation

• Available in indicating and non-indicating versions.

• No exhaust venting, flame boxes or reinforcing is required.

• Provide positive interruption even on low fault currents.

• Disconnect and non-disconnect mountings are available.

• Various sizes available for a wide range of applications.

• Current ratings from 1/2E to 10E are available at 600V to 34.5kV.


• These types of fuses are used on conjunction with potential and control power transformers.

• PT fuses are applied in industrial installations and commercial buildings for Potential Transformer and Control Power Transformer protection.


• E-rating: Over 100E must melt in 600 seconds (10 minutes) on 220 to 264% of E (ampere) rating. Example a 750E fuse must melt in 600 seconds with an applied current of 1650 to 1980 amperes.

• General Purpose Current-Limiting Fuse: A general purpose current-limiting power fuse is one that is capable of interrupting all currents from its rated interrupting rating down to the current that causes melting of the fusible element in one hour.


• Bussmann

• Eaton Cutler Hammer Westinghouse

• Ferraz Shawmut

• General Electric

• Littelfuse

• Cooper Power Systems



Type SM Fuses are especially suited for protecting transformers, capacitor banks, and cables in outdoor distribution substations on systems rated up through 34.5 kV.

They offer the superior performance characteristics and reliability required to provide twofold protection protection for the system upstream, and protection for downstream equipment.

Type SM Power Fuses from S&C Electric are offered with maximum continuous current ratings of 200, 300, 400, and 720 amperes, and are available with fault-interrupting ratings from 28,000 amperes RMS asymmetrical at 34.5 kV to 60,000 amperes RMS asymmetrical at 4.16 kV.

These power fuses are available in a variety of ampere ratings as well, and in three different speeds: Standard, Slow, and Coordinating. The broad selection of available ampere ratings and speeds permits close fusing to achieve maximum protection and optimum coordination. They may be operated (i.e., opened or closed when not carrying load) using a hook stick or a universal pole equipped with a variety of fuse-handling fittings


• No damageable silver or nickel-chrome fusible elements

• Provide precise and permanently accurate time-current characteristics

• Permit upstream protective devices to be set for faster operation

• Maximum continuous current ratings of 200, 300, 400, and 720 amperes


appl sc• Cables

• High Voltage Capacitors

• Pad Mounted Transformers


• The Refill Unit – The refill unit consists of a fusible element, arcing rods, and a solid-material arc-extinguishing medium contained within a filament-wound glass-epoxy tube. The fusible element is connected at one end through a current-transfer bridge to the refill unit lower ferrule. At the other end, the fusible element is connected to the main arcing rod, which extends upward through the main bore of the refill unit to the upper terminal. The auxiliary arcing rod, of stainless steel, is threaded into the upper terminal and extends downward through a small-diameter stepped bore and through an opening in the current-transfer bridge. No load current is carried by this auxiliary rod since, at its small-diameter section, it is insulated from the auxiliary arcing contact.

• Spring-and-cable assembly stainless steel spring provides high-speed elongation of arc within refill unit when fuse operates. Copper cable inside spring carries load (and fault) current


• S&C Electric



bfusesBottle fuses, also called Neozed type, are most commonly rated for 400-500V. They generally have 3-4 physical sizes and fit into special screw caps. There is non-interchangeability of fuse-links because of the graduated diameter of the bottom contacts, corresponding to the fixed diameter of the gauge piece. Screw caps fit onto single pole bases which are screw or DIN rail mounted. Some fuse-links have blown-fuse indicators which are visible through the screw cap.


• Variety of sizes

• Fit into special screw caps

• Pole or DIN rail mounted

• Blown fuse indicators are visible through the screw cap


• Industrial applications

• Inverters

• Drives

• Semiconductor protection

• Cable Protection



• Bussmann

• Ferraz Shawmut

• Siemens

• Siba