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Medium-voltage switchgear

Pad-mounted MOST fluid-filled switch

Eaton's Cooper Power series medium-voltage pad-mounted MOST fluid-filled switchgear provides economical underground switching and optional fuse protection. The switchgear offers switch designs that combine multiple functions on one switch, which allows for a quicker and more reliable operation.

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MOST oil switch catalog Fundamentals of medium-voltage switchgear
Modular design
Up to 6 ways of switches or fuses
FLuid-insulated, sealed design
Less intrusive than comparable designs
Deadfront construction
Minimizes high voltage safety hazards

Core features

  • Simple, economical approach to underground switching
  • Up to 6 ways of switches or fuses to meet specific requirements without the added cost of custom construction
  • High level of safety for both the operator and the general public with its deadfront design
  • Compact, low-profile unit that is considerably less obtrusive than comparable air-insulated designs

Fluid insulation provides for a compact, low-profile unit

Fluid insulation results in a considerably less obtrusive unit than comparable air-insulated designs. Insulating fluid also reduces maintenance and eliminates moisture, dirt and wildlife problems.
FR3 dielectric fluid

Ideal for utility, commercial and industrial applications

The wide selection of fuses available with the MOST fluid-filled switch make it easily adaptable to standardized distribution systems, and fits the majority of standard pads. The ELSG full-range current-limiting fuse provides consistent clearing of low currents as well as reliable high-speed interruption of high-magnitude short circuit currents. In addition to providing excellent protective characteristics over a wide range of applications, the “E” rated ELSG fuses have time–current characteristics that coordinate easily with other upstream and downstream protective devices.
ELSG full-range current-limiting fuse

Quicker and easier operation

Switched ways are available in four different positions: two-position open/close, four-position selector blade, four-position “V” blade and four-position “T” blade. Eaton’s “V” and “T” blade designs are unique in that they perform the function of three separate open/close switches. All switch operations are indicated on a single switch handle. Combining multiple functions on one switch not only permits quicker and easier operation but, in addition, makes possible a more compact unit.
MOST switch catalog

Operate in areas subject to moisture, flooding and snow

The deadfront, non-ventilated, tamper-resistant construction of low-profile MOST switchgear makes it suitable for operation in areas subject to excessive moisture, occasional flooding, and blowing snow. Additional sealing is provided by the Buna-N rubber gasket in the bolted cover. A full stainless steel construction option is available.
Specifications

Ratings

Normal voltage
 15 kV
 25 kV
 35 kV
Maximum design voltage
 15.5 27 38
BIL, kV
 95 125 150
1-minute withstand (60 Hz), switch* and terminators, kV
 35 60 70
Continuous current, amps (max.)
 600 300 200**
Load switching, A
 600 300 200**
Momentary current 10 cycles, A (asym.)
 16,000 16,000
 16,000
2 sec., A (sym)
 10,000
 10,000
 10,000
3 shot make and latch A (asym.)
 16,000
 16,000
 16,000
* The withstand rating of the switch is higher than that of the connectors (IEEE Std C37.74-2003 standard).
** An alternate two-position OPEN-CLOSE switch is available for 15 kV, 25 kV and 35 kV designs that have a 300 A continuous and load switching rating. This alternate switch meets IEEE Std C37.74-2003 standard requirements.

Fuses

ELSG kV Description MOST rating-kV
8.3

E rated, full-range current-limiting rating:

4, 8, 12, 15, 20, 25, 30, 40, 50, 60, 65, 80, 100 or 125 A

 15
15.5

E rated, full-range current-limiting rating:

4, 8, 12, 15, 20, 25, 30, 40, 50, 60, 65, 80 or 100 A

 25
23.0

E rated, full-range current-limiting rating:

4, 8, 12, 15, 20, 25, 30, 40, 50, 65, 80 or 100 A

 25 and 35
23.0

Equivalent to A.B. Chance fuse

SL54: 50 A

SL90: 90 A

 25 and 35

Accessories

  • 1/2" copper ground rod (in lieu of ANSI standard stainless steel ground points)
  • 1" drain valve with 3/8" sampler (in lieu of standard 1" drain plug and 3/8" sampler)
  • Fault indicator provisions, Qty. 6, located in the source or tap compartment sill
    • Source compartment
    • Tap compartment
  • 304L stainless steel construction (in lieu of standard mild steel construction)
  • Spare-fuse storage rack
  • T-Handle (for manual switch options)
  • Fuse drip tray
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In the wake of a storm or disaster, Eaton understands that safety and speed of response is everything. You can rely on Eaton Care teams to plan, protect and connect.

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