Medium Voltage Fuses
Medium Voltage Fuses
2,400 - 38,000 VAC • Current-Limiting
Current-limiting “E” and “R” rated fuses
are equipped with a mechanical indicator
or striker pin that protrudes through the
fuse cap upon operation of the fuse. This
provides visual identification of a blown
fuse and can be used as a trigger for
external devices.
Note: Extension distance 1/2” min; extension
force 2lb. min
General Information
The terms “Medium Voltage” and “High Voltage” have been used
interchangeably by many people to describe fuses operating above 600
volts. Technically speaking, “medium voltage” fuses are those intended
for the voltage range from 2,400 to 38,000 VAC. “High voltage” fuses
are for circuits carrying voltages greater than 38,000 VAC.
“E” rated fuses are considered to be general purpose fuses and can be
used to protect against low and high values of fault current. “R” rated
fuses are designed for back-up protection. They must be used in series
with other devices such as motor overload relays in order to achieve
both overload and short-circuit protection.
Medium voltage fuses are not intended to provide overload protection in
the same sense as fuses rated 600 volts or less. Medium voltage fuse
current ratings do not have the same meanings as the ampere ratings of
low voltage fuses.
Littelfuse now offers a complete selection of “E” and “R” rated
medium voltage fuses for the protection of transformers, potential
transformers, feeders, and motor circuits. Single, double, and triple
barrel designs are available to cover a wide range of current, voltage,
and interrupting ratings. Conventional ferrule type, clip lock, and bolt-in
mounting configurations are now available for virtually any application.
Hermetically sealed fuses for use in hazardous environments are also
offered.
All medium voltage fuses are limited in their ability to interrupt low value
overcurrents, especially those between 100% and 200% of the fuse’s
continuous current rating. They are designed to carry their rated current
without exceeding the temperature rise permitted by NEMA and ANSI
standards.
Additional application data can be found in the Fuse Application section
of this catalog.
Contact the factory or your local Littelfuse representative for additional
fuse ratings or custom mounting configurations.
24 Hour Emergency Service is available. Call 847 824 1188.
Applications
Power Transformer Protection
Potential Transformer Protection
Motor Controller Back-up Protection
Fused Switches
Feeder Circuits
Bolt-in Mount Fuses
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© 2005 Littelfuse POWR-GARD™ Products Catalog
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