SECTION 16470 PANELBOARDS PART 1 GENERAL 1.01 SUMMARY A. Related Sections: 1. 09900 - Painting. 2. 16120 - Wire and Cable. 3. 16475 - Overcurrent Protective Devices. 1.02 SYSTEM DESCRIPTION A. Performance Requirements: Materials shall bear Underwriter Laboratories (UL) labels. B. Panelboards used as service entrance equipment shall be UL labeled. 1.03 SUBMITTALS A. Submit manufacturer's literature and technical data before starting work. PART 2 PRODUCTS 2.01 MANUFACTURERS A. Panelboards: 1. General Electric. 2. I.T.E. 3. Siemens. 4. Square D. 5. Westinghouse. 2.02 EQUIPMENT A. Panelboards: 1. Interiors shall be factory assembled and designed to allow switching and protective devices to be replaced without disturbing adjacent units, without removing the Project No. SPECIFICATION GUIDELINES 16470-1
main bus connectors, and allowing circuits to change without machining, drilling, or tapping. 2. Branch circuits shall be arranged using double row construction unless narrow column panels are indicated. A nameplate shall be provided listing panel type and ratings. Circuit breakers shall be bolt-on type. 3. Unless otherwise noted, full size insulated neutral bars shall be included. Bus bar taps for panels with single pole branches shall be arranged for sequence phasing of the branch circuit devices. Neutral bussing shall have a suitable lug for each outgoing feeder requiring a neutral connection. A ground bus shall be provided in all panels. B. Boxes and Trim: 1. Boxes shall be at least 20 inches wide made from code gage galvanized sheet steel. a. Provide minimum gutter space according to NEC. b. Where feeder cables supplying the mains of a panel are carried through its box to supply other electrical equipment, the box shall be sized to include the additional required wiring space. c. At least 4 interior mounting studs with adjustable nuts shall be provided. 2. Switching device handles shall be accessible. a. Doors and panelboard trims shall not uncover any live parts. b. Doors shall have flush chrome plated handle with cylinder lock and catch, except doors over 48 inches in height shall have auxiliary fasteners top and bottom of door in addition to the flush type cylinder lock and catch. c. Panelboard switching devices with individual dead front doors shall be acceptable instead of standard door in trim design. d. Panelboard trim clamps shall be of the indicating type. 3. Door hinges shall be concealed. Locks shall be keyed alike. Furnish directory frame and card having a transparent cover with each door. 4. Exterior and interior steel surfaces of the trim shall be properly cleaned, primed with rust inhibiting Project No. SPECIFICATION GUIDELINES 16470-2
phosphatic coating, and finished with manufacturer's standard gray paint. a. Trims for flush panels shall overlap the box for at least 3/4" all around. b. Surface trims shall have the same width and height as the box. c. Trims shall be mountable by a screwdriver without the need for special tools. d. After installation, trim clamps shall not be accessible when the panel door is closed and locked. 5. Panelboards exposed to the weather shall have NEMA type 3R raintight enclosure or NEMA 4X in corrosive environments. C. Electrical Components: 1. Main bus bars shall be copper sized according to UL standards to limit the temperature rise on any current carrying part to a maximum of 50 degrees C. above an ambient of 40 degrees C. maximum. Provide main circuit breakers, main lugs, or sub-feed lugs as required. 2. Each panelboard shall incorporate breakers as shown with AIC or higher, at the application voltage, than the available fault at its location along the electrical distribution system, as determined by short circuit study. Minimum rating of breakers shall be: a. Lighting and power panels for use at 120/208 volts: 225 amp maximum with circuit breakers rated at 10K AIC symmetrical at 240 volts. Type B10B by Westinghouse or accepted equivalent. b. Lighting and power panels for use at 480/277 volts: 225 amp maximum with circuit breakers rated at 14K AIC symmetrical at 480 volts. Type WEHB Westinghouse or accepted equivalent. c. Distribution panels for use at 120/208 volts: UL listed with minimum integrated assembly rating of 22K AIC. Type Q22B by Westinghouse or accepted equivalent. 3. Panels tested and listed according to UL 67 and bearing an integrated short circuit rating shall be determined by the short circuit study on the electrical system with 10,000 AIC minimum. 4. Any 2 single pole circuit breaker shall be replaceable Project No. SPECIFICATION GUIDELINES 16470-3
by 1 two-pole circuit breaker and any 3 single-pole breaker shall be replaceable by 1 three-pole circuit breaker. 5. Where new circuit breakers are specified to be installed within existing panelboards, they shall be compatible in terms of manufacture, type, and AIC. 6. Distribution panelboards, 400 amperes and over, shall be provided with molded case circuit breakers tested and UL labeled according to UL 489. 7. Breakers 100 ampere through 400 ampere frame sizes shall be thermal-magnetic trip with inverse time current characteristics, unless otherwise noted. 8. Provide ground fault circuit interrupter circuit breakers where indicated. 9. Emergency Panelboards Identification: Paint door red and stencil in 1 inch high yellow letters "EMERGENCY PANEL" in addition to appropriate individual panel identification as shown on drawings. PART 3 EXECUTION 3.01 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. 3.02 INSTALLATION A. Install according to manufacturer's recommendations and applicable codes and regulations. B. Panelboards shall be installed where indicated and with top of cabinet 6'-6" above floor, and shall be rigidly and securely attached to building construction and shall not depend upon conduit for support. Allow at least 1/2" air space behind wall mounted panelboards. C. Install panelboards according to manufacturer's recommended data. Maintain clearances required by the National Electrical Code, with particular attention to working space around panelboards. Maintain clear space above panelboards, coordinate with other trades to avoid placement of panelboards below piping, ductwork, or other foreign appurtenances. Relocate panels at no additional cost should such interferences occur. Project No. SPECIFICATION GUIDELINES 16470-4
D. Supply panelboards with phenolic nameplate 1 inch x 3 inch on exterior of panels and engraved with panel designation and voltage rating. Lighting and power panelboards shall be provided with a clear plastic enclosed typewritten directory inside. Circuit identification shall include load type (lighting, receptacles, etc.) and rooms served. E. Where flush type panelboards are indicated, provide one 3/4" empty conduit terminated in accessible ceiling above for each 3 spare circuit breakers provided in the panelboard. F. Install circuit breakers in existing panelboards according to manufacturer's recommendation. Verify tightness of connections including mains. Identify new circuits on the panel directory. If none exists, provide one. G. Clean and touch up panelboard as required at completion of the project. END OF SECTION Project No. SPECIFICATION GUIDELINES 16470-5