2.2.2
Switch Construction
Bypass/isolation switch shall be constructed for convenient removal of
parts from front of switch enclosure without removal of other parts or
disconnection of external power conductors. Contacts shall be as specified
for associated ATS, including provisions for inspection of contacts without
disassembly of BP/IS or removal of entire contact enclosure. To facilitate
maintenance, manufacturer shall provide instructions for determination of
contact integrity. BP/IS and associated ATS shall be interconnected with
suitably sized copper bus bars silver-plated at each connection point, and
braced to withstand magnetic and thermal forces created at WCR specified
for associated ATS.
2.3
ENCLOSURE
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NOTE: Designer must provide normal power source to
ATS when specifying enclosure heater.
If ATS assembly is provided, equipment should be
installed in free-standing, floor-mounted enclosure
as specified, except when manufacturer incorporates
switch specified in wall-mounted enclosure as
standard construction. However, in some
applications it is advisable to specify that ATS or
BP/IS components be mounted in separate switchboard,
switchgear, motor control center, or other
enclosure. Designer shall investigate conditions
and options and specify accordingly.
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ATS and accessories shall be installed in [wall-mounted] [free-standing,
floor-mounted], [ventilated] [unventilated] NEMA ICS 6, Type [1] [3R] [4]
[12], smooth sheet metal enclosure constructed in accordance with
applicable requirements of UL 1066 and/or UL 1008. [Intake vent shall be
screened and filtered. Exhaust vent shall be screened.] [Door shall have
suitable hinges, locking handle latch, and gasketed jamb.]
[Thermostatically controlled heater shall be provided within enclosure to
prevent condensation over temperature range stipulated in paragraph SERVICE
CONDITIONS.] Metal gauge shall be not less than No. 14. Enclosure shall
be equipped with at least two approved grounding lugs for grounding
enclosure to facility ground system using No. [4] [_____] AWG copper
conductors. Factory wiring within enclosure and field wiring terminating
within enclosure shall comply with NFPA 70. If wiring is not color coded,
wire shall be permanently tagged or marked near terminal at each end with
wire number shown on approved detail drawing. Terminal block shall conform
to NEMA ICS 4. Terminals shall be arranged for entrance of external
conductors from [top] [bottom] [top and bottom] of enclosure as shown.
Main switch terminals, including neutral terminal if used, shall be
pressure type suitable for termination of external [copper] [aluminum]
conductors shown.
2.3.1
Construction
Enclosure shall be constructed for ease of removal and replacement of ATS
components and control devices from front without disconnection of external
power conductors or removal or disassembly of major components. Enclosure
of ATS with BP/IS shall be constructed to protect personnel from energized
BP/IS components during ATS maintenance.
SECTION 16410A
Page 14
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