Flushing Library Contract eBook

Division 01 - DDC STANDARDGENERAL CONDITIONS SINGLE CONTRACT PROJECTS Issue Date June 01, 2013 Revised - January 15, 2015

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DESIGN + CONSTRUCTION

5. For circuit breakers with frame size up to and including 225 Amperes, the breakers may be provided with non-interchangeable trip elements. For frame ratings above 225 Amperes, the breakers shall be provided with interchangeabletrip elements, which can be replaced readily. 6. Single pole circuit breakers for branch circuits shall have a frame size of no less than 100Amperes, and shall be rated at 125 volt A.C. with a NEMA interrupting rating of 10,000 Amperes, unless a higher rating is specified in the Specifications or indicated on the Contract Drawings. 7. INVERSE TIME ACTION: The circuit breakers shall be dual element type, one (1) element with time limit characteristics, so that tripping will be prevented on momentary overloads, but will occur before dangerous values are reached and the other with instantaneous trip action. Inverse time delay action shall be effective between a minimum tripping point of 125% of rating of breaker and an instantaneous tripping point between 600% and 700% of rated current. 8. CONSTANCY OF CALIBRATION: The tripping elements shall insure constant calibration and be capable of withstanding excessive short circuit conditions without injury. 9. CONTACTS: shall be non-welding under operating conditions and of the silver to silver type. 10. TEMPERATURE RISE: Current carrying parts, except thermal elements, shall not rise in temperature in excess of 30 degrees C. while carrying rated current at rated frequency. 11. NUMBERING: Each circuit breaker shall be distinctly numberedwhen installed in a group with other breakers. The calibration of trip element shall be indicated on each breaker. B. SAFETY SWITCHES: NEMA TYPE HD: When safety switches are permitted to be used for service entrance, motor disconnecting means or to control other types of electrical equipment, they shall be of the type HD of a rating not less than 30 Amperes. Enclosures shall be providedwith means for locking. For ratings above 60 Amperes terminals shall have double studs. 3.6 DISTRIBUTION CENTERS: This Section sets forth the construction and installation procedure for Switchboards, Panel boards and Cabinets. A. PANELBOARDS-GENERALTYPE: The panel boards shall be of the automatic circuit breaker type with individual breakers for each circuit, removablewithout disturbing the other units. Circuit breakers shall be in accordancewith the requirements outlined under "Circuit Protective Devices." B. NUMBERAND RATING OF CIRCUIT BREAKERS: The Contract Drawings show a layout of each panel, giving the number, frame, size and trip setting of circuit breakers and number of branch circuits and spare breakers. Each branch circuit shall be distinctly numbered. C. BUS-BAR CONSTRUCTION AND SUPPORT: Panel Boards shall be of the dead front type and shall have bus bars and branch circuits designed to suit the system and voltage. Current carrying parts, exclusive of circuit breakers shall be copper and based on a maximum density of 1,000 Amperes per square inch. Bus bars for the main switchboard shall be designed for the frame rating of the Service Breaker. Bus bars shall run up the center of the panel, unless otherwise indicated, and shall have connected thereto the various branch circuits. Unless otherwise specified, bus bars for each panel board shall be equipped with main lugs only and capacity as required on Contract Drawings. Where main protection is required, automatic circuit breakers shall be used. A neutral bus of at least the same capacity as a live bus bar shall be provided for the connection of all neutral conductors. Each terminal shall be identified. All current carrying parts, exclusive of circuit breakers, shall be of copper with a minimum number of joints. The bus bar structure shall be a self-supporting unit, firmly fastened to a ½ REFER TO THE ADDENDUM FOR THE APPLICABILITY OF SUB-SECTION 3.6

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