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Transcript
This master should be used by designers working on Port of Portland construction projects and by designers working for PDX
tenants (“Tenants”). Usage notes highlight a few specific editing choices, however the entire section should be evaluated and
edited to fit specific project needs.
SECTION 263600 - TRANSFER SWITCHES
PART 1 - GENERAL
1.1
DESCRIPTION
A.
1.2
This section describes transfer switches rated 600 V and less, including the following:
1.
Automatic transfer switches.
2.
Nonautomatic transfer switches.
REFERENCES
A.
NEMA: National Electrical Manufacturers Association
B.
NETA: International Electrical Testing Association
C.
UL: Underwriters Laboratories
1.
UL 508: Industrial Control Equipment
1.3
SUBMITTALS
A.
Product Data: Submit for each type of product indicated. Include rated capacities, weights,
operating characteristics, furnished specialties, and accessories.
B.
Shop Drawings: Dimensioned plans, elevations, sections, and details showing minimum
clearances, conductor entry provisions, gutter space, installed features and devices, and material
lists for each switch specified.
C.
Contract Closeout Submittals:
1.
Provide operation and maintenance data.
PART 2 - PRODUCTS
2.1
AUTOMATIC TRANSFER SWITCH
A.
General:
1.
The transfer switch, complete with all timers, relays, and accessories, shall be UL-listed
under Standard UL-1008 and approved for use on emergency systems. The UL listing
shall include the specific amperage ratings that are called for on the drawings.
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TRANSFER SWITCHES
263600-1
2.
3.
4.
5.
6.
7.
8.
9.
The transfer switch shall have a short circuit withstand capability and closing ratings
when coordinated with circuit breakers in excess of the UL minimum requirement of
42,000 RMS amperes symmetrical.
The transfer switch shall be completely wired, assembled, and tested by the manufacturer
at the factory to ensure compatibility and to completely test the assembly.
Provide the transfer switch as shown on the drawings with full load current rating of
amperes at 277/480V, 3-phase, 4-wire, 60 Hertz AC normal and emergency.
The transfer switch shall be capable of switching all classes of load and shall be rated for
continuous duty when installed in non-ventilated enclosures.
Provide exercise timer, automatically actuated, to permit weekly programming of engine
generator test runs under load. If the emergency source should fail during the exercise
period, and if normal power is available, the switch shall immediately restore to normal.
Auxiliary contacts shall be provided to monitor the status of the ATS.
Transfer switches shall be microprocessor controlled with front accessible HMI interface.
Transfer switches shall be listed and rated as service equipment.
B.
Transfer Switch Construction:
1.
Inherent 4-pole switched neutral type with all four poles on a common shaft.
2.
Double-throw actuated by two electrical operators momentarily energized and connected
to the transfer mechanism by a simple over-center type linkage with a minimum transfer
time of 400 MSEC. Provide an adjustable pneumatic timer, 0 to 60 seconds, on delayed
equipment transfer switch.
3.
Capable of transferring successfully in either direction with 70 percent of rated voltage
applied to the switch terminals.
4.
The normal and emergency contacts shall be positively interlocked mechanically and
electrically to prevent simultaneous closing. Main contacts shall be mechanically locked
in position in both the normal and emergency positions without the use of hooks, latches,
magnets, or springs and shall be silver tungsten alloy protected by arcing contacts with
magnetic blowouts on each pole.
5.
Equipped with safe manual operators that are designed to prevent injury to the operating
personnel if the electrical operation should suddenly become energized during manual
transfer. The manual operator shall provide the same contact transfer speed as the
electrical operator in order to prevent a flashover caused by switching the main contacts
too slowly.
6.
Include pilot lights on the enclosure door to indicate the switch closed on normal or
emergency, and four auxiliary contacts on the main shaft, two closed on normal, and two
closed on emergency. Load test switch to simulate normal power failure. All relays,
timers, control wiring, and accessories shall be front accessible.
7.
Voltage Sensing:
a.
The automatic transfer switch shall be provided with voltage sensing relays for
each phase. Connection of these sensing relays shall be made to the normal power
input terminals of the transfer switch. Voltage range shall be field adjustable.
C.
Transfer switches shall include a two position selector switch to select either automatic or
manual transfer operation with pushbuttons to transfer to emergency and re-transfer to normal.
D.
Each automatic transfer switch shall be installed in an enclosure with locking hinged door
conforming to NEMA ICS and complying with the requirements of UL 508.
E.
Main terminals requiring field wiring connections shall be suitable for copper wiring.
TRANSFER SWITCHES
263600-2
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F.
Automatic transfer switches shall be suitable for satisfactory performance when installed for
operation at 200-feet altitude, 40°C high and minus 20°C low ambient temperature, 90 percent
relative humidity.
G.
Color of the finish coat of paint shall be manufacturer’s standard.
H.
Acceptable manufacturer is Russelectric “RMTD” type, or pre-bid approved equal.
2.2
NONAUTOMATIC TRANSFER SWITCHES
A.
Operation: Electrically actuated by push buttons designated “Normal Source” and “Alternate
Source.” Switch shall be capable of transferring load in either direction with either or both
sources energized.
B.
Double-Throw Switching Arrangement: Incapable of pauses or intermediate position stops
during switching sequence.
C.
Nonautomatic Transfer-Switch Accessories:
1.
Pilot Lights: Indicate source to which load is connected.
2.
Source-Available Indicating Lights: Supervise sources via transfer-switch normal- and
alternate-source sensing circuits.
a.
Normal Power Supervision: Green light with nameplate engraved “Normal Source
Available.”
b.
Emergency Power Supervision: Red light with nameplate engraved “Alternate
Source Available.”
2.3
UNASSIGNED AUXILIARY CONTACTS
A.
One set of normally closed contacts for each switch position, rated 10 A at 240-V ac.
PART 3 - EXECUTION
3.1
INSTALLATION
A.
Neatly lace and secure the conductors of the feeder circuits individually at maximum 2 foot
intervals. The cable lugs shall not support the weight of the cables.
B.
Identify components according to Section 260533, Identification for Electrical Systems.
C.
Automatic Transfer Switch:
1.
Install automatic transfer switch as shown on the drawings and according to the
manufacturer’s recommendations.
D.
Concrete Pads:
1.
Provide minimum 3-inch-thick concrete housekeeping pads under all free-standing pieces
of switchgear. Pads shall extend a minimum of 2 inches beyond the edges of the
equipment.
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TRANSFER SWITCHES
263600-3
3.2
STARTUP, TESTING, AND TRAINING
A.
All tests shall comply with NETA standards.
B.
Perform startup and testing of the equipment after installation has been completed.
C.
Testing:
1.
Set time delays and sensing control wiring for automatic start/stop operation and time
delays between transfer switches.
2.
Fully test switch operation. Tests shall be witnessed by the Port.
D.
Upon completion of the onsite tests, a general inspection shall be made for:
1.
Any deficiency which may impair proper operation.
3.3
ACCEPTANCE
A.
Final acceptance will not be granted by the Port until onsite tests have been successfully
completed, all defects in material or operation have been corrected, and operating and
maintenance data has been submitted along with all completed test reports.
END OF SECTION 263600
TRANSFER SWITCHES
263600-4
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