GE Industrial Solutions Entellisys Low Voltage Switchgear - Manuel (Page 17)

Entellisys Low Voltage Switchgear
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3-7 Compartments for Future Breakers
When specified, compartments may be supplied for future
addition of circuit breaker elements. These compartments are
fully equipped with drawout rails, primary disconnects, and
ancillary devices as required (i.e. secondary disconnects,
accessory devices, etc.) The opening in the breaker compartment
door (3), Fig. 3-13, is closed with a bolted-on steel plate (2) to deter
accidental contact with energized electrical circuits.(i.e. primary
disconnect stabs).
1. Quarter-turn latch
2. Steel plate (future breaker cubicle)
3. Future cubicle door cover
Fig. 3-12. Future breaker compartment cover (padlockable ¼ turn
latch will be provided on future breaker cubicles)
3-8 Auxiliary/Transition Sections
These sections may be provided for any one or more of several
reasons including:
• Transition to a close-coupled transformer
• Incoming cable or busway when a main breaker section is
not provided
Auxiliary sections may be 22-inch, 30-inch, or 38-inch wide as
required to accommodate the space requirements. The
compartment doors on the front of the sections are hinged and
latched in the same manner as breaker compartment doors.
Generally, transition sections will be 22-inches wide for close-
coupling to transformers.
Power company metering requirements generally require either a
38-inch or 49-inch wide auxiliary section to accommodate the
current transformers, meters, test switches, etc. as required by
their individual practices, and/or regulatory commissions.
3-9 Bus Area
The bus area, Fig. 3-13, contains the main horizontal bus and
vertical riser bus bars (1) for the particular section. The vertical
bus bars are supported at the breaker run-ins (2) which are bolted
to the molded bases (3) that form the rear wall of the breaker
compartment. The horizontal bus bars are supported by the
power connectors which are bolted to the vertical bus bars. All
bolted supports and connections are accessible from the rear for
maintenance. The bus area is fully isolated from the breaker,
instrument and auxiliary compartments by the molded bases or
glass polyester sheet.
1 Vertical riser bus
2. Run-ins to breaker compartment
3. Molded base
4. Run-backs from breaker compartment
5. Short-circuit brace
Fig. 3-13. Bus construction
Busing System
Bus bars are fully tin-plated copper with bolted joints and silver
plating is optional. The standard construction is open bus. A
barrier system (Bus compartmentation) that isolates the main and
vertical bus bars from the cable area is available as an option. All
run-backs (load-side power conductors) from the breaker
compartment to the cable termination area are covered with non-
PVC insulated tubing.
The typical arrangement is shown in Fig. 3-14.
The standard bracing is 65,000 amperes, RMS symmetrical.
Bracing for 100,000 amperes, RMS symmetrical is available as an
option.
In general, when the switchgear equipment has no more than four
sections or does not exceed 10 feet in length, it will be shipped as
one complete lineup. In such cases, the only field assembly would
be to a close-coupled transformer if, the switchgear were part of a
Load Center Unit Substation. If, because of shipping and/or
handling considerations, the equipment cannot be handled in one
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