S&C high voltage fusesS&C Electric Company is a global provider of equipment and services for electric power systems. Founded in 1911, the Chicago-based company designs and manufactures switching and protection products for electric power transmission and distribution. S&C high voltage fuses provide a reliable and economical means of protecting small to medium-sized transformers installed in utility and industrial substations.


S&C high voltage fuse type SM offer superior performance and reliability providing both upstream and downstream protection. They are suited for protecting transformers, capacitor banks, and cables in outdoor distribution substations on systems rated up through 34.5 kV. They offer 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.


Determine the volt-ampere or VA rating for the primary side of the transformer (the high-voltage side) by multiplying the voltage and amperes and dividing the product by 1000. The result is the transformer’s input amperage. S&C Electric provides this handy selection guide to assist you in choosing the right fuse.


These high voltage fuses are available three different speeds: standard, slow, and coordinating and are made of non-damageable silver or nickel-chrome fusible elements. The wide selection of available ampere ratings and speeds allow close fusing to achieve maximum protection and coordination. They may be operated (i.e., opened or closed when not carrying load) using a hookstick or a universal pole equipped with a variety of fuse management fittings.