Electrical fire pump with emergency generator

In this case study, an onsite generator must provide the secondary source of power for the fire pump.


Figure 2: Power feed to the fire pump is shown via a direct connection from a utility transformer. Courtesy: WSP + ccrdThe building's normal power service is supplied from a pad-mounted utility transformer that is fed by a singular utility substation. The authority having jurisdiction has deemed that the single utility service is not considered a reliable source, so it cannot be the only supply source for the fire pump. An onsite generator must provide the secondary source of power for the fire pump. The service to the fire pump will need to meet the requirements as defined by NFPA 70: National Electrical Code (NEC) 695.3(B)(2) for service from an individual source and onsite standby generator.

The primary supply to the fire pump controller will come directly from a connection at the utility transformer. This was coordinated with the utility company; most will allow for this separate connection to be tapped at the transformer. This meets the requirement for continuity of power as defined by NEC 695.4(A) (direct connection). The feeder from the switchgear to the fire pump controller (located in a different area) will be routed below the building floor slab so that it is considered outside the building per NEC 230.6(1).

The second source for the fire pump will come from the emergency power system for the building. The building's generator system will be sized to handle the starting and normal operating load of the fire pump as defined by NED 695.3(D)(1). A circuit breaker, sized to accommodate normal start-up of the pump, will be located in the emergency distribution board. The second feeder will route overhead to the fire pump controller and be encased in a minimum of 2-in. concrete.


Sarah Kuchera is senior vice president and electrical engineer at ccrd + WSP. Her duties have included project management, production coordination, and project engineering on a variety of different projects including hospital, retail, hospitality, and office buildings. 

Product of the Year
Consulting-Specifying Engineer's Product of the Year (POY) contest is the premier award for new products in the HVAC, fire, electrical, and...
40 Under Forty: Get Recognized
Consulting-Specifying Engineer magazine is dedicated to encouraging and recognizing the most talented young individuals...
MEP Giants Program
The MEP Giants program lists the top mechanical, electrical, plumbing, and fire protection engineering firms in the United States.
November 2018
Emergency power requirements, salary survey results, lighting controls, fire pumps, healthcare facilities, and more
October 2018
Approaches to building engineering, 2018 Commissioning Giants, integrated project delivery, improving construction efficiency, an IPD primer, collaborative projects, NFPA 13 sprinkler systems.
September 2018
Power boiler control, Product of the Year, power generation,and integration and interoperability
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
Data Center Design
Data centers, data closets, edge and cloud computing, co-location facilities, and similar topics are among the fastest-changing in the industry.
click me