Fusesplay a major role in protection of electrical circuits, loads and
operators. Fuses are used to protect against short circuit under extremely high
currents, as well as overload. They are suitable for use in the protection of
transformers, electric motors, magnetic and solid-state control assemblies and
power distribution runs, just to name some of their many applications in
industry today.
There are a number different types of fuses used
in industry. Common categories are high-voltage, current limiting, resettable
fuses, and thermal fuses (described below). Some of the major manufacturers of
fuses are Busman, GE, Cutler-Hammer, Littlefuse and Ferraz-Shawmut (Mersen).
Fuse Holders are devices for containing, protecting and mounting fuses. Fuse holders come in two basic types, open or fully enclosed. Open fuse holder types are fuse clips, fuse blocks, socket and plug-on cap varieties. The fully enclosed variety may use a fuse carrier that is inserted into a holder or have other means to fully enclose the fuse.
Standard fuse sizes range from ¼” diameter, 5/8” length (1AG) to ¼” diameter 1” length (8AG), to 5mm x 20 mm, pico fuses and automotive blade. "Automobile Glass" fuses use the term "AG" in the fuse size designation. Bakelite fiber, ceramic or other similar material fuses use the term "AB" instead of "AG" in the size designation, but retain the dimensions of the "AG" types. Automotive blade fuse sizes differ from glass tube sizes due to the shape of the fuse. Important performance specifications to consider when searching for fuse holders include normal operating current, rated operating voltage, and power dissipation capacity. The maximum power dissipation (self-heating) of the fuse used with the fuse holder. Also called the Rated Power Acceptance. The minimum conducting path or conductor cross-sectional area of the conductor connected to the fuse holder should also be considered.