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.
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.
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.
Medium Voltage Fuses
Applications
Power Transformer Protection
Potential Transformer Protection
Motor Controller Back-up Protection
Fused Switches
Feeder Circuits
Bolt-in Mount Fuses
64
www.littelfuse.com
© 2005 Littelfuse
•
POWR-GARD
™
Products Catalog
Medium Voltage Fuses
E Rated Medium Voltage Fuses
Current-Limiting
“E” Rated fuses have time current characteristics designed to
provide current-limiting protection for power transformers, potential
transformers, power centers, feeder centers, and unit sub stations.
When properly applied, they can protect against high and low fault
currents.
NEMA Standards for “E” rated medium voltage fuses require that
fuses rated 100E or less open within 300 seconds (5 minutes) when
subjected to an RMS value of 200-240% of the fuse continuous current
rating; and fuses with an “E” rating larger than 100E must open within
600 seconds (10 minutes) when subjected to an RMS current of 220-
240% of the fuse’s continuous current rating. These values establish
one point on the time-current curve.
Characteristics
Voltage Rating: 2,400 volts – 38,000 volts
Current Range: 10E – 600E
Options
• Hermetically sealed for use in hazardous locations
(add “S” suffix to part number)
• Clip-lock (CL) and bolt-in styles available.
Application Note:
Since these fuses are used for the protection of general purpose
circuits which may contain transformers, motors, and other equipment
producing in-rush and/or overload currents, fuses should generally be
rated at 140% of the normal full load current, and circuits should be
analyzed to ensure that system load currents will not exceed the current
rating of the fuse.
3"DIA
6.38"
9.75"
Medium Voltage Fuses
Dim.A
(Clip
Center)
Dim.B
Figure 14
D
Figure 15
DD
Figure 16
DDD
E
Rated
Catalog Number
10E-1C-2.75
15E-1C-2.75
20E-1C-2.75
25E-1C-2.75
30E-1C-2.75
40E-1C-2.75
50E-1C-2.75
65E-1C-2.75
80E-1C-2.75
100E-1C-2.75
125E-1C-2.75
150E-1C-2.75
200E-1C-2.75
125E-2C-2.75
150E-2C-2.75
175E-2C-2.75
200E-2C-2.75
225E-2C-2.75
250E-2C-2.75
300E-2C-2.75
350E-2C-2.75
400E-2C-2.75
450E-2C-2.75
Old Catalog Number
LCX 10E
—
—
—
LCX 30E
LCX 40E
LCX 50E
LCX 65E
LCX 80E
LCX 100E
—
—
—
LCX 125E
LCX 150E
LCX 175E
LCX 200E
—
LCX 250E
LCX 300E
—
LCX 400E
—
Size
10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
125E
150E
200E
125E
150E
175E
200E
225E
250E
300E
350E
400E
450E
Dim. A (inches)
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
Dim. B (inches)
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
Max Interrupting
Rating RMS (Asym)
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
AA
Figure Number
14
14
14
14
14
14
14
14
14
14
14
14
14
15
15
15
15
15
15
15
15
15
15
2.75 Max. KV
© 2005 Littelfuse
•
POWR-GARD
™
Products Catalog
www.littelfuse.com
69
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