Edited by Bluekayak, 23 January 2010 - 03:38 PM.
NEC Fire Pump Requirements
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Posted 23 January 2010 - 03:36 PM
Typically fire pump circuits are supplied by a tap made ahead of the main disconnecting means in the service equipment [per Article 230-82(5) of the 2008 NEC]. Per NEC Article 695-3(a)(1) the tap is not permitted in the same cabinet, enclosure, or vertical switchboard section as the service disconnecting means. So if the main service is supplied by a 2500kVA, 12470V-480Y/277V transformer (obviously not dedicated to the fire pump circuits) and the tap for the fire pump circuits is made as previously described, then the code permits overcurrent protectective devices to be installed ahead of the fire pump circuits in the power supply for either utility or customer-owned supply systems as long as these protective devices are selected or set to carry indefinitely the sum of the locked-rotor current of the fire pump motor(s) and the pressure maintenance pump motor(s) and the full load current of the associated fire pump accessory equipment. See Article 695-4 for verification of this requirement. So, my interpretation of the code is that Article 695-5 refers to transformers that are dedicated to the fire pump circuits (primary overcurrent protection only). Any insight into my interpretation would be greatly appreciated.
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