the buses, circuit breakers, and switchgear to which the bus is connected,
unless otherwise indicated. The bus shall conform to the requirements of
IEEE C37.23. Bus shall be of the nonsegregated-phase type. [A ground bus
[is] [is not] required.] [A neutral bus [is] [is not] required.] The
enclosure is to be the nonventilated type constructed of selected smooth
sheet steel not less than [_____] mm gauge, and shall be equipped with
continuously energized space heaters (with high-temperature thermal
protection) to prevent condensation over an ambient temperature range of
[minus 29] [_____] to [40] [_____] degrees C [minus 20] [_____] to [104]
[_____] degrees F. The finish of the enclosure shall be in accordance with
the manufacturer's standard. The finish, type, and gauge of the metal
enclosure and the details of transitional elements and connections and the
lengths and ratings of the bus and enclosure proposed shall be as shown on
2.7
OUTGOING METAL-CLAD SWITCHGEAR
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NOTE: Designer will show on contract drawings the
locations of all items specified in other paragraphs
that will be located in the metal-clad switchgear.
Where two-high units are used, consult
manufacturer's literature and catalogs for available
options. Ancillary devices such as PTs and metering
will not fit in the switch compartment and require a
separate compartment or top hat section.
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Switchgear shall comply with NEMA SG 6 and IEEE C37.20.2 and shall be of
the outdoor [no-aisle] [protected-aisle] [common-aisle] type consisting of
incoming line [, tie,] auxiliary compartments and feeder circuit breaker
units. Compartments shall be provided to accommodate specified or
indicated auxiliary equipment. The indicated number of active and [future]
circuit breakers and equipped cubicles shall be provided. ["Future"
circuit breaker means sufficient concrete pad space and duct line stubouts
for future sections.] [The use of two-high circuit breaker units is
acceptable.] [Two-high circuit breaker units shall be provided.] [When
two-high circuit breaker units are installed, equipped space units shall be
provided when necessary to make adjacent sections equal in height.] [Units
denoted as equipped space or future shall consist of items of equipment
listed for the basic unit in NEMA SG 6, except the power circuit breaker
shall not be provided.] [Current transformers, instruments, instrument
switches, and relays shall be provided for equipped space or future units
as shown.] [Continuous current rating of future units shall be as
indicated.] [Continuous current rating of equipped space units shall match
the most common basic breaker unit ampere rating used elsewhere in the
associated switchgear unless otherwise indicated.] Switchgear shall be
vented according to the manufacturer's standard practice. Intake and
shown. The control voltage shall be [120 V ac] [240 V ac] [24 V dc] [48 V
dc] [125 V dc] [250 V dc].
2.7.1
Ratings
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NOTE: ANSI C37.06, Table 2, lists preferred ratings
for indoor oilless circuit breakers. A
short-circuit study is required to specify ratings.
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SECTION 16311A
Page 40
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