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NFPA 20, Standard for the Installation of Stationary Fire Pumps for Fire Protection, establishes the minimum requirements for the selection, installation, and performance of fire pump systems. When electric motors are used to drive fire pumps, NFPA 20 places strict emphasis on reliability, electrical safety, and continuity of operation during fire conditions. While NFPA 20 does not define motor voltage classes such as “medium voltage” or “high voltage,” it references voltage thresholds and defers many electrical installation requirements to NFPA 70 (NEC).

NFPA 20 permits electric motors as prime movers for fire pumps provided they are specifically listed and approved for fire pump service. The standard requires that electric motor–driven fire pumps be supplied by a reliable power source and that the electrical system be designed to minimize the possibility of interruption during a fire event. The voltage rating of the motor directly influences how the electrical supply and protection systems are designed and installed.

In practice, medium-voltage fire pump motors typically operate above 1,000 V AC and are used where pump horsepower requirements exceed the practical limits of low-voltage motors. NFPA 20 allows the use of medium-voltage motors provided the entire electrical system—including controllers, feeders, disconnecting means, and overcurrent protection—is suitable for the voltage and arranged to ensure reliable starting and operation.

NFPA 20 requires that fire pump controllers be listed for the voltage and horsepower of the motor. For medium-voltage systems, this often results in the use of reduced-voltage or across-the-line medium-voltage controllers specifically designed and listed for fire pump duty.

NFPA 20 recognizes that electric fire pump motors may be supplied from systems exceeding 1,000 V AC, but it does not provide detailed electrical installation rules for these voltages. Instead, NFPA 20 explicitly relies on NFPA 70 (NEC) for conductor sizing, insulation requirements, grounding, clearances, and disconnecting means for over-1,000-volt systems.

The intent of NFPA 20 is that high-voltage fire pump installations achieve the same or higher level of reliability as low-voltage systems, while maintaining adequate protection against fire, electrical faults, and mechanical failure.

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