Section 4 – Installation

1. Remove all packaging material. Keep the shipping pallet attached to the Unit Substation to assist with moving the unit to its final installation location.

2. Verify that the nameplate matches the description from the building layout drawings (kVA, primary and secondary voltages, etc.). See Sample Nameplate.

   Sample Nameplate

   

3. Locate the unit per the building’s layout drawing.

4. Verify the environment is suitable for the enclosure type.

5. Ensure the location is readily accessible to qualified personnel (per NEC 450.13). Units located in the open can be mounted on walls, columns, or otherwise supported from structures.

6. Ensure adequate ventilation since it is essential to properly cool Unit Substations.

   1. The minimum distance is marked on the nameplate. See Minimum Distance marked on Nameplate.

   2. Minimum distance varies by enclosure style. See the approval drawing from Schneider Electric for minimum distance.

   3. Clean, dry air is desirable.

   4. Filtered air may reduce maintenance if the location of the Unit Substation presents a problem.

      Minimum Distance marked on Nameplate

      

7. Place the Unit Substation in final position.

   The hardware must be supplied by the customer. The designer of record must size and choose the anchors and hardware because of the large variety of construction materials and techniques. Schneider Electric cannot advise on anchoring of the device.

   Mounting Layout

   

1. Permanently and adequately ground the enclosure and core assembly of dry-type transformers in accordance with NEC requirements.

Seismic limits for Unit Substations are obtained from tri-axle shake table test results that are conducted in accordance with the AC156 test protocol. Certifications are based on the location where units are installed and building codes governing the installation.

Building codes results are available for CBC 2001, CBC 2007, CBC 2010, IBC 2000, IBS 2003, IBC 2006, IBC 2009, NBC 2005, NBCC 2005, NBCC 2010, NFPA 5000, UBC 94, CBC 95, UBC97 and UFC 3-310-04. Contact your local Schneider Electric distributor, or call 1-888-Square D (1-888-778-2733) to obtain the specific level of Sds, z/h and Ip for each enclosure style.

The levels supplied are based on the units being mounted and the notes on the approval drawings of each part number. Drawings are available that include mounting dimensions, mounting hole dimensions, overall dimensions, unit weight and approximate center of gravity location to assist in a seismic qualification. Contact your local Schneider Electric distributor, or call 1-888-Square D (1-888-778-2733) to obtain these drawings.

Other parties are responsible for detailing the equipment connection and anchorage requirements (including the lateral restraint system, if appropriate) for the given transformer installation. The installer and manufacturers of the anchorage and lateral restraint system are responsible for ensuring that the mounting requirements are met.

• Use flexible raceways, conduits and connectors, when possible, as attachments to Unit Substation enclosures. This will help to reduce audible noise generation.

• Adhere to NFPA 70 (NEC) and minimum wire bending space requirements for the Unit Substation enclosure. As an industry standard, bundle associated phase, neutral and equipment grounding conductors together within the Unit Substation enclosure.

• Always use a calibrated torque wrench to tighten electrical connectors and terminals. For additional guidance, refer to Standard UL468A.

• Ensure that raceways, conduits and connectors enter the enclosure only in an area shown on the drawings. Access points for each enclosure style are listed below:

  NOTE: Refer to detailed dimensional drawings for exact size and location of conduit access points.

  Access Point: Enclosure Styles: MPUA

  

  Access Point: Enclosure Styles: MPUB and MPUC

  

  Access Point: Enclosure Styles: MPZA, MPZB, MPZC, MPZAA, MPZBB and MPZCC

  

1. Determine the wiring or conduit requirements for the main and branch circuits, as required by local electrical codes.

2. Select the proper cable clamp or use other approved methods for securing the cable or conduit to the enclosure.

3. Remove the appropriate knockouts or create conduit opening in the designated areas required for installation of cable clamps or conduit. To remove the knockouts, see Removing the knockouts.

   Removing the knockouts

   

4. Open the cover and lock in the open position using the locking slots in the top of the enclosure. See Locking cover in open position.

   Locking cover in open position

   

5. Remove dead front and primary circuit breaker cover to gain access to wiring compartment.

1. Pull the conductors into the enclosure. Use approved wire clamps, conduit bushings, or other approved methods to secure the conductor to the enclosure and prevent damage to the conductor insulation.

   NOTE: Use wire insulated for a minimum of 194°F (90°C) and sized on the basis of 140°F (60°C) ampacity.

2. Connect the main wires.

   1. Install the main wires according to the wiring diagram on the transformer. See .

   2. Connect the service ground, equipment grounding wire, or both as required by the local electrical code.

   3. Torque each connection to the value specified on the circuit breaker.

      Mini Power-Zone Wiring diagram

      

   4. If this equipment is used for service entrance in the United States, as permitted by the National Electric Code, then apply “Service Disconnect” label near the Main circuit breaker.

WARNING
hazard of equipment damage This equipment is designed and tested by Schneider Electric™ to performance levels which exceed Underwriter’s Laboratories® (UL®) standards and Mexican Official Standards (NOM) listing. Use only Square D™ brand circuit breakers and accessories. Failure to follow these instructions can result in death, serious injury, or equipment damage.

QO and QOB Circuit Breaker Removal

Refer to QO and QOB Circuit Breaker Installation and Removal for the following instructions:

1. Turn OFF all power to the panelboard.

2. Remove the load wire.

3. Disengage the branch connector.

   For QO Circuit Breakers:

   1. Pull outward until the plug-on jaws fully disengage the branch connector.

   For QOB Circuit Breakers:

   1. Loosen the screw in the circuit breaker connector and pull the circuit breaker off of the branch connector.

4. Snap the wire terminal end of the circuit breaker off of the mounting rail.

QO and QOB Circuit Breaker Installation and Removal

If the circuit breaker is tripped, the handle will be at the mid-position between ON and OFF. To reset the circuit breaker, push the handle to the OFF position, then to the ON position.

Circuit Breaker Handle Positions

1. Remove the cover twistouts. Remove the appropriate twistouts to match the number of circuit breakers being installed. See Removing Twistouts.

2. Identify the circuit breakers on the directory label.

3. Install the deadfront using the screws provided and torque to 20 lbs-in
   (2.3 N•m).

4. Fill any unused circuit breaker openings with the filler plates.

Removing Twistouts

1. Ensure that all of the packing material, including any packing material used inside the enclosure of the Unit Substation used to support and protect the unit during shipping, have been removed.

2. Vacuum away as much dust as possible. Dust will act as a thermal insulating material which will increase the temperature of the unit and could possibly decrease operational life. Refer to Cleaning.

• Perform the following visual and mechanical checks below. In addition, refer to Performing Visual and Mechanical Checks for a detailed listing of instructions.

• Visually inspect the Unit Substation for physical damage. Repair any physical damage, if possible, and provide suitable protective barriers to prevent future damage.

• Compare the Unit Substation nameplate information with the drawings and/or specifications for the installation.

• Verify proper connection of the taps in accordance with the nameplate information.

• Check the clearance of all electrical connections. Verify all connections for tightness with a calibrated torque wrench.

• Visually check the enclosure, conduits, raceways and conductors for proper ground bonding. In addition, refer to Grounding and Bonding.

• Verify all unused taps are isolated and insulated.

DANGER

hazard of electric shock, explosion, or arc flash Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E (NEC). NOM-029-STPS-2011, or CSA Z462. This equipment must be installed and serviced only by qualified electrical personnel. Perform such work only after reading and understanding all of the instructions contained in this bulletin. Turn off all power supplying this equipment before working on or inside equipment. Always use properly rated voltage sensing device to confirm power is off. Always practice lock-out/tag-out procedures according to OSHA requirements. Carefully inspect your work area, and remove any tools and objects left inside the equipment. Replace all devices, doors, and covers before turning on power to this equipment. All instructions in this manual are written with the assumption that the customer has taken these measures before performing maintenance or testing. Failure to follow these instructions will result in death or serious injury.

Refer to Section 6 – Maintenance to perform the following pre-commissioning electrical testing:

• Measure contact resistance using a low resistance ohmmeter. Refer to Contact Resistance.

• Perform insulation resistance tests with an appropriate device. Refer to Insulation Resistance.

• Perform a turns ratio test on all taps and on the full winding voltages for each phase. Refer to Turns Ratio.