Appendix P - HC102812R0067.pdf

Page 1 of 5 Version Date: 11 May 2010

DISA Computing Services Division (CSD) Facilities Engineering Team (CD521)

MINIMUM TECHNICAL SPECIFICATIONS

FOR

POWER DISTRIBUTION UNIT (PDU)

1. SCOPE.

Scope: This specification covers the technical requirements for a power center and will be referred to as a Power Distribution Unit (PDU) that provides suppression, isolation, distribution, and monitoring for electrical branch circuits supporting computer equipment.

The picture of a sample PDU to the right is for illustrative purposes only and does not indicate any preference for model or manufacturer. The unit shown would not meet all of the specifications herein; it does not have an adequate number of subfeed breakers. The hinged doors, hinged panelboard access doors, and a general configuration for a PDU are illustrated.

2. APPLICABLE STANDARDS.

The PDU will be designed, manufactured, tested, and installed in compliance with the following mandatory standards:

• National Fire Protection Association (NFPA) Code 70 - National Electrical Code (NEC)

• American National Standard for Electrical Power Systems and Equipment Voltage Ratings (60 Hz), ANSI C84.1

• Underwriters Laboratory (UL) Listed in accordance with UL 60950, standard for information technology equipment at date of manufacture.

• Fully CSA Listed at date of manufacture.

• Current version of the DISA Facilities Standards CSI 360-95-3

• NFPA 75, Standard for Protection of Information Technology Equipment

• NEMA, National Electrical Manufacturers Association

3. REQUIREMENTS.

3.1 PDU Electrical Requirements.

3.1.1 Capacity. The PDU will have a minimum output capacity of 125 kVA 150 kVA 175 kVA 225 kVA with a minimum of three (3) subpanels (see paragraph 1) and 2 1 subfeed breakers for remote distribution cabinet (RDC or “expansion cabinet”) capabilities.

3.1.1.1 PDUs that are natively designed with only two (2) subpanels are acceptable provided they are capable of being expanded with an affixed cabinet (sidecar) providing the third subpanel. This affixed cabinet must open to the front of the unit and not require side access during maintenance or installation of circuits, to match the requirement of paragraph 3.5.3 below.

3.1.2 Input. The input voltage to the PDU will be 480 volts alternating current (ac) at 60 hz, three phase. As required by the PDU’s base design, barriers shall be installed to prevent personnel that are installing branch circuits from any exposure and/or contact with the 480VAC sections of the PDU.

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All panelboards will be connected to the input power feed. Input power conductors shall connect to manufacturer-supplied and –installed mechanical lugs supplied by the manufacturer with the equipment. Compression/crimp-type lugs that fit over the conductor are not acceptable. Only those of construction similar to that shown (to the right) are acceptable, sized for the necessary amperage and conductor diameter (minimum #10-2/0) necessary to operate the unit at full capacity. These power connection points shall be provided for connection of the three phase conductors, a 173% rated neutral and a parity-sized insulated ground.

3.1.3 Output voltage. The output from the PDU shall be 208Y/120 volts ac at 60 hz, three phase, four-wire-plus ground wye secondary configuration.

3.1.4 Wiring and Bussing: All wiring and bussing components internal to the PDU shall be copper.

3.1.5 Transformer. The PDU will have an electro-statically shielded, K-20 rated transformer for reduction of harmonic distortion. The transformer will provide step-down for the input 480 volts to 208Y/120 volt PDU output. The transformer will be dry type, three phase, common-core, convection air cooled. The transformer will conform to ML-T-27B, with Class H, 220 degrees C minimum insulation. All transformer windings shall be copper.

Audible noise levels of the transformer will be less than the ANSI C89 standard for transformers. The transformer will be provided with six full capacity compensation taps at 2.5% increments to accommodate field adjustments to match source voltage. These compensation taps will be easily accessible by removal of one exterior panel. Tap changes include:

• Two, 2.5%, full capacity, above nominal (maximum 5% above)

• Four, 2.5%, full capacity, below nominal (maximum 10% below)

Typical characteristics exhibited by the transformer will be:

• Percent impedance – 3.5%

• Percent reactance – 3.0%

• Common mode noise attenuation- 55 db minimum

• Common transverse conversion mode noise attenuation –80 db

• Full-load efficiency – 97%

The transformer will be provided with additional thermal overload protection for the transformer. An alarm shall notify personnel if transformer temperature reaches 180 degrees Celsius. The PDU will automatically shut down if transformer temperature reaches 200 degrees Celsius.

3.1.6 Spike/Transient Suppression. The PDU’s input and output will be equipped with Spike/Transient Voltage Suppression to clip high-energy transients and provide filtration and suppression of line-energy transients and provide filtration and suppression of line noises. The spike and transient suppression shall be located and protected so that personnel installing branch circuits are not exposed to the suppression system components.

3.1.7 Ground. Per NEC 250.30 the PDU will be connected to the buildings grounding electrode. Provide a termination point that is electrically connected to the ground and XO bond on the secondary side of the transformer.

This connection point shall be clearly marked.

3.1.8 Main Input Circuit Breaker. The PDU will be equipped with a UL-listed main input circuit breaker to provide a means of disconnecting power to the PDU. The main input circuit breaker shall be mechanically connected to the PDU’s input, main input breakers that are “snap in” type are not permitted. The main input breaker will provide overcurrent protection for the transformer and system coordination with the other overcurrent protection devices. It will be a three-pole thermal magnetic molded case circuit breaker rated for industrial use. It will be rated for 600 VAC and will be sized for 125% of the PDU full-load input current in accordance with National Electric Code. The minimum UL-listed interrupting ratings for the main input circuit breaker will be 35,000 RMS symmetrical amperes at 480 volts ac. The breaker will include a 25 VDC shunt trip mechanism to interface with Emergency Power Off mechanisms as required by NEC. A label will be provided to clearly identify the breaker as the main input breaker.

Example of mechanical lug necessary to connect input and ground conductors to unit for proper operation.

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The main input breaker shall be located and protected so that personnel installing branch circuits are not exposed to the breakers input or output terminals and/or wiring.

3.1.9 Manual Restart. When the PDU is equipped with a manual restart feature to allow for an orderly supervised startup after system shutdown, the default configuration for this option shall be "Automatic", meaning that the main input circuit breaker shall trip only under overcurrent and local Emergency Power Off situations.

3.1.10 Distribution Panel boards. The PDU will be provided with a minimum of three (see paragraph 1 above for number of panel boards based on unit kVA rating) vertically mounted and forward facing output panel boards for distribution to the intended loads. Each panel board will be three-phase and have a rating of 225 amperes with a minimum overall short-circuit current rating of 22,000 RMS symmetrical amperes. Each panel board will be capable of mounting single-pole, two-pole, and three-pole circuit breakers. The panel boards will utilize Square D

General Electric with Plug-In Bolt-In type circuit breakers sized through 100 amperes.

3.1.10.1 Each panelboard will have 42 pole positions so that the PDU will have a total of 126 (minimum) pole positions. Guides will be installed between the branch circuit breaker bus bar connections. Each output distribution panelboard will be electrically isolated and individually protected by a main panelboard circuit breaker that will provide overcurrent protection for the panelboard and allow shutdown of the individual panelboard.

3.1.10.2 Each panelboard will be individually enclosed with separate hinged covers to provide access to each panelboard without exposing the other panelboards or any of the 480V electrical components.

3.1.10.3 Each individual panelboard will include separate isolation neutral and safety-ground bus bars for the neutral and safety-ground connections from each branch load. The ground and neutral bus bars for each panelboard shall be located adjacent to the panelboard that they support. The ground and neutral bus bar connections shall be clearly marked.

3.1.11 Each subfeed breaker position shall be factory populated with a 225A breaker with a minimum overall short-circuit current rating of 22,000 RMS symmetrical amperes. When the customer connection point for the load side of the subfeed breakers is of bus type, mechanical lugs (see section 3.1.2 above) for all subfeed connections shall be provided. The lug types shall support the installation of 4/0 conductors for the three phases and neutral connections and #4 AWG for the ground connection.

3.1.12 Distribution panel boards shall come empty of any branch circuit breakers with blank space fillers installed in place of the breakers.

3.1.13 Branch Circuit Breakers and Circuits. Branch circuits will be fed from the bottom of the PDU into the raised access floor. Means to connect flexible, metallic, liquid-tight conduits will be easily obtained by use of installed internal conduit-landing plates. All wiring, terminations, and components associated with the PDU’s 480V components and the 208V panelboard inputs shall not be routed through, terminate in or protrude into the space allotted for installation of branch circuit conductors or raceways.

3.5 Frame and Enclosure.

3.5.1 The frame will be of welded steel construction. The unit shall have lockable, removable, hinged front and rear doors that are 16-gauge perforated sheet metal construction to maximize ventilation. A two-point latch (“door handle”) with key lock shall be provided for security and Lockout Purposes. The front doors shall provide access to the main panelboard circuit breakers and to all branch circuit breakers, means for accessing the 480V components and sub feed breakers are not required to be accessed from the front doors. The enclosure will be of sheet metal partitions that attach to the frame by means of attachment mechanisms that allow the partitions to be removed from the sides and back. The PDU will have permanent leveling jacks for final installation.

3.5.2 Doors and side panels are finished in electrostatic powder-coat black cream.

3.5.3 The unit will be installed against a wall in a open space.

For units that are installed against the wall, the unit shall be manufactured so that maintenance of the unit’s transformer and other electrical components can be performed from the front and side of the PDU. The panelboard orientation shall comply with section 3.1.10 of this document.

For units that are being installed in an open space, front and rear side access is permissible for maintenance of the transformer and other electrical components. The panelboard orientation shall comply with section 3.1.10 of this document.

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3.5.4 In order to fit into DISA-standard master floorplans, the footprint of the unit shall be no greater than 48” 60” width (not including access door opening swing and clearance requirements) and maximum of 36” 48” depth to accommodate doorway entrances.

3.5.5 The distributed weight of the PDU shall be less than 250 lb/ft2 (1225 kg/m2).

3.5.6 The PDU shall be provided with a stand shall not be provided with a stand. When provided, the floor stand shall be sized to carry the full weight of the PDU with all of the PDU’s legs resting on the floor stand. Floor stands shall be adjustable to account for minor variations in floor surface condition and level. The floor stand shall position the PDU even with the raised floor surface and to minimize static pressure loss between the unit and any gap to the floor surface. The floor stand shall be designed to equally distribute the weight of the PDU across the structural floor below the raised floor without interfering in the electrical installation of the PDU or any of its branch circuits. The floor stand shall be seismically rated for seismic zone none II III IV. The depth of the raised floor, as measured from structural floor to top of raised floor is enter height (inches) here inches.

3.6 Ground. The PDU will have a computer grade, single point ground.

3.7 Emergency Power Off. The PDU will have a fully-guarded and illuminated Emergency Power Off switch to power down the PDU under emergency conditions

3.8 Monitoring.

3.8.1 Local Monitoring. The PDU will have a local monitoring panel affixed to the unit and will be a microprocessor-based system that includes the following:

• Voltage Monitoring – will include the ability to select and monitor both input and output voltage line-to-line and output voltage line-to-neutral for all three phases.

• Current Monitoring – will include the capability to select and monitor all three phase currents (input and output), the neutral and the ground current.

• Power Monitoring - will include the capability to monitor the total output as measured in kilovoltamps, kilowatts, and the associated power factor.

• Branch Circuit Monitoring – The PDU shall have circuit monitoring installed on all of the units branch circuits. The current transformer that is installed for each branch circuit shall be size to support a 60 Amp branch circuit. The PDU’s branch circuit monitoring shall be capable of being retrofitted with current transformers to support a 100 Amp branch circuit.

• Alarming – At a minimum, the PDU will visually and audibly report the following alarms:

o Output Overcurrent o Neutral Overcurrent o Phase Sequence Error o Transformer Over temperature o Input overvoltage o Input undervoltage o Output undervoltage o Frequency deviation o Phase Loss o TVSS and Surge Suppression activation o TVSS and Surge Suppression failure

3.8.2 Remote Monitoring. The PDU shall be capable of communicating with an external building automation system via an open protocol communication platform. Remote monitoring interfaces that require additional

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Page 5 of 5 Version Date: 11 May 2010 manufacturer specific interface devices to communicate with the PDU are not acceptable. Acceptable communication protocols are: Modbus (TCP preferred), BacNet, & SNMP. Wiring, terminations and programming to connect the PDU to the building automation system will be provided and installed by others. The remote monitoring package must be able to communicate all of the PDU’s metering and alarming functions listed in section

3.8.1 of this specification.

4. DELIVERY.

4.1 Inside delivery is required for all PDU equipment.

5. TESTING.

5.1 Factory Testing. The PDU will be completely factory tested before shipment.

6. SERVICE.

6.1 Maintenance. The manufacturer will provide one year of any manufacturer’s recommended scheduled preventative maintenance on the equipment at no additional cost to the Government.

7. WARRANTY.

7.1 The manufacturer shall provide a standard manufacturer’s warranty for one year from date of installation/start-

up. The warranty shall include a guarantee against defects in materials and workmanship.

7.2 The warranty shall cover all parts found to be defective at no additional cost to the Government.

8.0 START-UP.

8.1 Provide 7x24 commissioning of the PDU with the time and date of the PDU to be scheduled by DISA. Upon completion of the PDU commissioning, provide written commissioning documentation to the DISA site POC and to the assigned DISA facilities engineering department’s electrical engineer for the project.

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