For fire pump circuit protection, the required rating is 125% of the fire pump motor full-load current and 100% of the associated fire pump accessory equipment.

• A. 125% of motor FLC and 100% of accessory equipment
• B. 100% of motor FLC and 125% of accessory
• C. 125% of motor FLC and 125% of accessory
• D. 100% of motor FLC and 100% of accessory

Answer: (A)

Sizing fire pump circuit protection balances enough headroom for starting the motor with proper protection for the other equipment. The fire pump motor draws a large inrush when it starts, so the overcurrent protection must be rated higher than the running current to avoid nuisance trips during startup. Using 125% of the motor’s full-load current gives that necessary margin. The associated fire pump accessory equipment, such as control gear and alarms, doesn’t typically have the same startup surge, so protecting it at 100% of its full-load current provides adequate protection without oversizing. This combination ensures reliable starting of the pump while keeping accessories properly protected.