M-DCPS MASTER SPECIFICATION GUIDELINES

1 Project Name M-DCPS MASTER July 99 Project No. SPECIFICATION GUIDELINES 16460 - 1 SECTION 16460 DRY-TYPE TRANSFORMERS PART 1 GENERAL SUMMARY A. Related Sections: 1. 16120 - Wires and Cables. 2. 16450 - Grounding. SYSTEM DESCRIPTION A. Performance Requirements: Materials shall bear Underwriters Laboratories (UL) labels. SUBMITTALS A. Submit manufacturer's catalog cuts and technical data before starting work. B. Submit test data for transformers as requested. QUALITY ASSURANCE A. Dry type transformer installation shall comply with NFPA 70 National Electrical Code (NEC). PART 2 PRODUCTS MANUFACTURERS A.

2 Dry Type Transformers: 1. General Electric Corp. 2. ITE. 3. Square D. 4. Westinghouse. EQUIPMENT A. Rating: 1. Transformers shall be ventilated dry type, 3 phase, 60 Hertz, 480 volts delta primary and 208Y/120 volts secondary, with four 2-1/2 percent FCBN taps and two 2-1/2 percent FCAN taps. KVA rating shall be as shown on Project Name M-DCPS MASTER July 99 Project No. SPECIFICATION GUIDELINES 16460 - 2 drawings. 2. Transformer insulation shall be Class "H", 220 degrees Centigrade insulation systems and shall be rated for operation (150 degrees C. rise above 40 degrees C. ambient). Insulating materials shall be according to NEMA ST20 standards. 3. Transformer sound level shall not exceed following values when measured according to ANSI : 9 KVA to 45 KVA-45 DB, 50 to 150 KVA-50 DB, 150 to 300 KVA-55 DB.

3 DESIGN AND CONSTRUCTION A. Core and coil assembly shall be vacuum impregnated for maximum resistance to moisture and shall be mounted on vibration isolation pads. 1. Transformers shall be provided with a drip-proof, rodent-proof, enclosure, having a durable finish and a rustproof diagrammatic nameplate. 2. Wiring compartments shall have adequate space for terminating cables and shall be front connected for easy accessibility. 3. Where transformers are exposed to the weather, provide weather shields. B. Core of the transformer shall be of high quality, cold-rolled, grain oriented steel, annealed by manufacturer for low loss and exciting current. 1. Laminations shall be formed to eliminate burrs and annealed to reduce losses to a minimum. 2. Winding conductors shall be annealed and insulated by transformer manufacturer.

4 3. Conductor surfaces shall be free from slivers, burrs, and other irregularities. PART 3 EXECUTION INSPECTION A. Do not proceed with the work of this section until conditions detrimental to the proper and timely completion of the work have been corrected in an acceptable manner. INSTALLATION A. Dry type transformers shall be installed by Contractor according to manufacturer's instructions in rooms assigned Project Name M-DCPS MASTER July 99 Project No. SPECIFICATION GUIDELINES 16460 - 3 for the installation of equipment. B. Transformer enclosures and secondary neutral shall be securely grounded to a cold water pipe, 3/4" diameter by 10 feet long buried in direct contact with the earth, with a copper conductor sized according to NEC Table 250-94. C.

5 Dry type transformers shall be floor mounted or bracket mounted as shown on drawings. Transformers shall be bolted to floor if floor mounted and shall be bolted to steel angles if bracket mounted, or as shown on drawings. Provide a 3 inch high concrete pad under floor mounted transformers. D. Transformers shall be vibrationally isolated from the building structure by means of double neoprene pads (DNP), in addition to the vibration isolation built into the transformer. Neoprene shall be similar to Mason Industries Type W, 40 durometer minimum or sized for proper weight load. E. Conduit connections to the equipment shall be made with flexible conduit, loosely installed. F. Dry type transformers shall be installed with wiring compartment to front to allow removal.

6 G. Maintain manufacturers recommended clearness from walls or surfaces to allow adequate ventilation. In no case shall the transformers be installed less than 6 inches from any wall. END OF SECTION