MD ANDERSON Project No. XX-XXXX
A/E Name
A/E Project No.
MD ANDERSON PROJECT NAME
Issue Description
Month, 00, 0000
SECTION 26 36 23 – 600 VOLT AUTOMATIC TRANSFER SWITCHES
PART 1 - GENERAL
1.01
RELATED DOCUMENTS
A. Drawings and general provisions of the Contract, including General Conditions and Division
01 Specification Sections, apply to this Section.
B. Specifications throughout all Divisions of the Project Manual are directly applicable to this
Section, and this Section is directly applicable to them.
C. Section 26 09 13 - Power Status and Monitoring System
D. Section 26 32 13 - Packaged Engine Generator Systems
E. Section 26 23 13 – 600 Volt Generator Paralleling Switchgear
1.02
SUMMARY
A. This Section specifies the furnishing and installation of automatic transfer switches. Where
indicated on the Drawings, switches are to have integral isolation/bypass switches.
1.03
REFERENCE STANDARDS
A. The latest published edition of a reference shall be applicable to this Project unless identified
by a specific edition date.
B. All reference amendments adopted prior to the effective date of this Contract shall be
applicable to this Project.
C. All materials, installation and workmanship shall comply with the applicable requirements and
standards addressed within the following references:
1. ANSI/UL 1008 - Automatic Transfer Switches.
2. NEMA ICS 1-109 - Dielectric Strength Test.
3. NEMA ICS 2-447 - A-C Automatic Transfer Panels.
4. NFPA 20 - Standard for Centrifugal Fire Pumps (for switches utilized with fire pumps).
5. NFPA 70 - National Electrical Code.
6. NFPA 99 - Essential Electrical Systems for Health Care Facilities.
7. NFPA 110 - Standard for Emergency and Standby Power Systems.
8. IEEE 446 - IEEE Recommended Practice for Emergency and Standby Power Systems for
Industrial and Commercial Applications.
9. IEEE 241 - IEEE Recommended Practice for Electrical Power Systems in Commercial
Buildings.
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10. IEEE 666 – Design Guide for Electric Power Service Systems for Generating Stations.
1.04
QUALITY ASSURANCE
A. Manufacturer qualifications. A minimum of ten years’ experience in the design, manufacture,
and testing of 600 volt automatic transfer switches is required. The manufacturer’s facility
shall be ISO 9001 certified.
1.05
SUBMITTALS
A. Product Data and Record Documents:
1. Include the following information in the submittal:
a. Rated current, voltage and frequency.
b. Number of poles.
c.
UL 1008 3-cycle close and withstand rating.
d. Physical dimensions.
e. NEMA enclosure type.
f.
Itemized list of accessories.
g. Schematic diagram (show wiring and only those components which are part of
switch).
h. Show all factory wiring on wiring diagram and clearly indicate all wiring and
connections to remote devices which are to be made in the field. (Show only that
wiring which pertains to switch and remote devices.)
i.
1.06
Indicate control wiring for communications package.
SERVICE AND WARRANTY
A. 600 volt automatic switch manufacturer shall have an established network of service centers
capable of servicing the specified equipment. The nearest service center shall be within 50
miles of the Project Site.
B. Service center and manufacturer's personnel shall be on call 24 hours a day, 365 days a year.
Factory train and certify personnel in the maintenance and repair of the equipment.
C. Warranty. The manufacturer shall warrant the unit against defects in workmanship and
materials for 5 years after initial start-up.
1.07
COORDINATION WITH UTILITY COMPANY
A. The Contractor shall, on behalf of the Owner, coordinate with utility company in providing
required information for reviewing and assuring that installation will meet utility requirements
as well as Electric Substantive Rules set forth by Public Utility Commission of Texas, which
governs technical requirements for interconnection and parallel operation of on-site distributed
generation and utility company distributed generation.
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PART 2 - PRODUCTS
2.01
GENERAL
A. All materials shall meet or exceed all applicable referenced standards, federal, state and local
requirements, and conform to codes and ordinances of authorities having jurisdiction.
Products or similar model in design (with L-shaped interlock device made of phenolic
material) that is known for causing incident in MD Anderson facilities within the past eight
years shall not be selected.
B. Provide automatic transfer switch (ATS) which is electrically operated and mechanically held
in each direction, and which is true double-throw. ATS shall be closed transition type.
C. Provide ATS with number of poles, voltage and current ratings as shown on the Drawings.
D. Each ATS shall consist of an inherently double-throw power transfer switch unit and a control
module interconnected to provide complete automatic operation.
E. Provide a microprocessor control panel.
2.02
MANUFACTURERS
A. The ATS manufacturer shall maintain a local service center capable of emergency service or
routine preventive maintenance and shall offer preventive maintenance contracts.
B. Manufacturers.
1. ASCO.
2. Russelectric.
2.03
CONSTRUCTION
A. The transfer switch unit shall be electrically operated and mechanically held.
B. The electrical operator shall either be a single or dual motor design with over-center type
linkage solenoid mechanism, momentarily energized to minimize power consumption and
heat generation.
C. The switch shall be positively locked and unaffected by voltage variations or momentary
outages so that contact pressure is maintained at a constant value and temperature rise at
the contacts is minimized for maximum reliability and operating life.
D. The switch shall be mechanically interlocked to ensure only one of two possible positions normal or emergency for single solenoid design and three possible positions - normal off,
emergency for dual motor design.
E. All main contacts shall be silver-plated copper composition. All switches shall have
segmented, blow-on construction for high withstand current capability and be protected by
separate arcing contacts.
F. ATS utilizing components of molded-case circuit breakers, contactors or parts thereof which
have not been intended for continuous duty, repetitive switching or transfer between two
active power sources are not acceptable.
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G. Inspection of all contacts (movable and stationary) shall be possible from the front of the
switch without disassembly of operating linkages and without disconnection of power
conductors. An insulated manual operating handle shall be provided for maintenance
purposes.
H. Utilize quick-make quick-break contacts mounted so that contact position may be verified by
observation.
I.
All terminal lugs shall be compression, AL/CU Type.
J.
All neutral conductors shall be connected solidly with a fully-rated AL/CU compression
connection.
K. Automatic Transfer Switch Controls
1. The transfer switch shall be equipped with a programmable microprocessor based control
system, to provide all the operational functions of the automatic transfer switch. The
controller shall have two asynchronous serial ports. The controller shall have a real time
clock with Ni-Cad battery back-up.
2. The CPU shall be equipped with self-diagnostics, which perform periodic checks of the
memory I/O and communication circuits, with a watchdog/power fail circuit.
3. The controller shall use industry standard open architecture communication protocol for
high-speed serial communications via multidrop connection to other controllers and to the
plant. The serial communication port shall be RS485 and Modbus protocol.
4. The controller shall have password protection required to limit access to qualified and
authorized personnel.
5. The controller shall include a twenty-character, LCD display, with a keypad, which allows
access to the system.
6. The controller shall include three-phase over/under voltage, over/under frequency,
phase sequence detection and phase differential monitoring on both normal and
emergency sources.
7. The controller shall be capable of storing the following records in memory for access
either locally or remotely.
a. Number of hours transfer switch is in the emergency position (total since record
reset).
b. Number of hours emergency power is available (total since record reset).
c.
Total transfer in either direction (total since record reset).
d. Date, time, and description of the last four source failures.
e. Date of the last exercise period.
f.
Date of record reset.
8. The microprocessor controller shall meet the following requirements:
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a. Storage conditions – 25°C to 85°C.
b. Operation conditions – 20°C to 85°C ambient.
c.
Humidity 0 to 99% relative humidity, noncondensing.
d. Capable of withstanding infinite power interruptions.
L. Closed transition. When designing a closed-transition system, it is imperative that the system
be designed with interlocks that prevent the inadvertent and indefinite paralleling of sources.
The following design rules should be used when designing closed-transition system.
1. Closed-transition switchgear should be designed such that manual transfers are manually
initiated and automatically interlocked. This prevents utility sources from being paralleled
for an excessive amount of time. This transition shall take place within the range of 100
milliseconds, depending on specific utility requirements.
2. Closed-transition switchgear should be designed with a non-defeatable safety-circuit
timing relay, which will cause source disconnection within a predetermined time if the
sources are manually paralleled, or the closed-transition interlocking scheme fails to
perform. For example, a timing relay that opens the tie breaker if both utility mains are
closed for 10 sec would serve this function.
3. Where closed-transition automatic transfer switches are specified, a shunt-trip circuit
breaker on the normal power feeder could be specified to force the normal power feeder
to open in the case of a failed-closed transition.
4. All of the functions noted in 1-3 above should be alarmed and annunciated.
2.04
OPERATION
A. The voltage of each phase of the normal source shall be monitored, with pickup adjustable
from 85 to 100 percent and dropout adjustable from 75 to 98 percent of pickup setting, both in
increments of 1 percent, and shall be fully field-adjustable. Repetitive accuracy of settings
shall be + 2 percent or better over an operating temperature range of -20 degrees C to 70
degrees C. Factory set to pick up at 90 percent and drop out at 85 percent.
B. Single-phase voltage sensing of the emergency source shall be provided, with a pickup
adjustable from 85 to 100 percent (and dropout fixed at 84 to 86 percent of pickup), and
frequency sensing with pickup adjustable from 90 to 100 percent (and dropout fixed at 87 to
89 percent of pickup). Both pickup settings shall be fully field adjustable. Repetitive accuracy
of settings shall be  2 percent or better over an operating temperature range of -20 degrees
C to 70 degrees C. Factory set to pick up at 90 percent voltage and 95 percent frequency.
C. The control module shall include four (4) time delays that are fully field adjustable in
increments of at least 13 steps over the entire range as follows:
1. Time delay to override momentary normal source outages to delay all transfer switch and
engine starting signals. Adjustable from 0 to 6 seconds. Factory set at 1 second.
2. Transfer to emergency time delay. Adjustable from 0 to 5 minutes. Factory set at 0
minutes, unless indicated otherwise on the Drawings.
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3. Retransfer to normal time delay. Time delay is automatically bypassed if emergency
source fails and normal source is acceptable. Adjustable from 0 to 60 minutes. Factory
set at 30 minutes.
4. Unloaded running time delay for emergency engine generator cool-down. Adjustable from
0 to 60 minutes. Factory set at 5 minutes.
D. A set of DPDT silver composition contacts rated 10 amps, 32 VDC shall be provided for a
low-voltage engine start signal when the normal source fails. The start signal shall prevent
dry cranking of the generator by requiring the generator to reach proper output, and to run for
the duration of the cool-down setting, regardless of whether the normal source restores
before the load is transferred.
E. Provide a pushbutton to bypass time delay on retransfer to normal.
F. A momentary-type test switch shall be provided to simulate a normal source failure.
G. Output terminals to signal the actual availability of the normal and emergency sources, as
determined by the voltage-sensing pickup and dropout settings for each source, shall be
provided.
H. Provide the following sets of dry auxiliary contacts rated 10 amps 480 VAC wired to an
accessible terminal strip. Building automation system (BAS) Provider shall connect these
contacts to the BAS for remote monitoring:
1. Two (2) contacts closed when the ATS is connected to normal;
2. Two (2) contacts closed when the ATS is connected to emergency;
3. Two (2) contacts closed when the normal power is available; and
4. Two (2) contacts closed when emergency power is available.
a. It is unacceptable to have one (1) form C contact to account for more than one of the
specified auxiliary contacts.
I.
Provide four (4) sets of signal lights to indicate the following:
1. When the ATS is connected to normal source;
2. When the ATS is connected to emergency source;
3. When normal power is available; and
4. When emergency power is available.
a. Form C contacts are unacceptable. Contacts shall be wired to an accessible terminal
strip.
J.
Each switch shall be furnished with an operator's manual providing installation and operating
instructions.
K. On all switches not part of a bypass isolation switch assembly, provide an external emergency
manual operator, UL listed for transferring the switch to either source under load.
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L. Provide LED type indicating lights; one to indicate normal power (green), one to indicate
emergency (red). Provide indicating lights for both normal and emergency availability.
M. Bypass/Isolation operation.
1. Provide a bypass/isolation switch to electrically bypass and isolate each automatic
transfer switch. The switch must be capable of bypassing to whichever source the ATS is
connected to.
2. The bypass/isolation switch also permits continuous service in case the transfer switch is
inoperable, damaged, or removed.
3. All auxiliary circuits to the automatic transfer switch remain in service during operation of
the bypass/isolation switch. Interlocking shall be provided to prohibit personnel from
controlling the sequence of operations and to prevent operation to the isolation position
until the bypass function has been completed.
N. Inphase monitor.
1. If the ATS is of a single solenoid design, an inphase monitor shall be built-in to the ATS
and shall control transfer so that motor load inrush currents do not exceed normal starting
currents, to avoid nuisance tripping of circuit breakers and possible mechanical damage
to motor couplings.
2. The inphase monitor shall operate without external control of electrical loads and without
any external control of the power sources.
3. The monitor shall compare the phase relationship and frequency difference between the
normal and emergency sources and permit transfer the first time the sources are within
15 electrical degrees and only if transfer can be accomplished within 60 electrical degrees
as determined by monitoring the frequency difference.
4. Inphase transfer shall be accomplished if both sources are within 2 Hz of nominal
frequency and 70 percent or more of nominal voltage. This is not required for dual motor
design.
O. Center off position. If the ATS is of the dual motor design, a time delay relay shall be provided
to vary the center off delay from 0 to 60 seconds.
P. Provide an elevator pre-signal before transfer to Normal after operating on Emergency during
an outage. Provide pre-signal for testing and for switching during transfer between energized
sources.
2.05
MAIN CONTACT PROTECTION AND WITHSTAND CURRENT RATINGS
A. Protect main contacts by providing arc barriers on each contact, and on switches rated above
300 amperes by providing separate arcing contacts.
B. The ATS shall be UL 1008 listed for a 3-cycle close and withstand current rating as indicated
on the Drawings. Series rating of switches with particular circuit breakers or fuses is not
acceptable.
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NEUTRAL BAR
A. Provide a 100 percent rated neutral bar with the same capacity as the ampere rating of the
switch, unless otherwise noted on the Drawings.
2.07
ENCLOSURE
A. Provide NEMA 1 switch enclosure suitable for wall or floor mounting.
B. Mount the bypass/isolation switch in a common enclosure with the associated transfer switch.
Separate the bypass/isolation switch from the associated transfer switch by a metal divider
panel.
C. Make the switch operable from a dead-front location.
padlocked in the bypass/isolation position.
Design switch so that it can be
D. Permanently attach wiring diagrams and maintenance instructions on the inside of enclosure
door in a mounting designed to hold the data. Instructions shall be laminated.
PART 3 - EXECUTION
3.01
INSTALLATION
A. Installation shall meet or exceed all applicable federal, state and local requirements,
referenced standards and conform to codes and ordinances of authorities having jurisdiction.
B. All installation shall be in accordance with manufacturer’s published recommendations.
C. Install the automatic transfer switches as shown on the Drawings.
D. Painting: Restore any marred surfaces to factory finish.
E. Equipment Settings. Properly set adjustable time and the adjustable parameters. Effectively
accomplish grounding and bonding.
F. Inspection. Thoroughly inspect the switches for items such as loose connections and
presence of foreign materials and remedy prior to energizing the switch. Bolted connections
shall be torqued to the manufacturer's recommendations.
G. Prior to energizing, check metering and control wiring for correct polarity and proper
interconnection.
H. Subsequent to completion of control and power circuit connections, energize switches and
verify functioning of metering and controls.
I.
3.02
Install nameplate on front door of the ATS cubicle. In addition, provide a "Danger High
Voltage, Keep Out" sign mounted on doors providing access to high voltage, as required by
NEC, OSHA, and Owner regulations and/or requirements.
TESTING
A. Test the switches with the packaged electric generator set in operating condition.
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B. Demonstrate to the Owner that the automatic transfer switches and bypass isolation switches
perform all required functions.
C. Coordinate with the commissioning agent for field tests and commissioning of the 5kV
automatic transfer switches in conjunction with the rest of the emergency power system,
including engine generators provided under Section 26 32 13 and emergency generator
paralleling switchgear provided under Section 26 36 25.
D. Notify the Engineer and the Owner's Representative 14 working days in advance of this test
date so the tests can be properly witnessed.
E. After completion of field testing, restore permanent electrical distribution system connections.
Repair connections, terminations, or conductors damaged or found to be defective during the
system full load test.
3.03
COMMUNICATIONS
A. Make provision for communication of switch alarms/status/data to emergency generator
paralleling switchgear. The contractor shall provide interconnecting circuitry between engine
generator units, automatic transfer switches, and emergency generator paralleling switchgear
as required.
B. Coordinate with engine-generator units, and generator paralleling switchgear for required
alarm/status/data signals. Refer to sections 26 32 13 and 26 36 25 respectively.
C. ATS shall be provided with a critical load monitor. See Specification section 26 09 13 Power
Status and Monitoring System and drawings.
3.04
TRAINING
A. Formal training for the operation and maintenance of all equipment and systems specified
herein shall be given by factory trained and certified personnel.
B. Training shall consist of a minimum of two, complete 4-hour training sessions.
C. Timing of the training should coincide with the schedule for the manufacturer's
representatives to be on Site for testing and Start-up of the systems.
D. The specified training shall be given at a location designated and provided by the Owner for a
minimum of ten (10) personnel selected by the Owner, in addition to any necessary on-Site
orientation and training.
E. A training program shall be submitted with material, instructors' qualifications, and proposed
schedule, a minimum of 60 days prior to the proposed training.
F. The Owner reserves the right of approval of any training course, material, instructor and
schedule.
END OF SECTION 26 36 23
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