A magnetic across-the-line starter is selected for a 25-horsepower motor operating at 460 volts. Under the general horsepower-rating rule in 2023 NEC 430.83(A)(1), what rating must that controller have?
- A horsepower rating of at least 25 hp at the applied voltage
- BAn ampere rating chosen solely as 250 percent of table motor current
- CA horsepower rating determined solely by the motor’s locked-rotor code letter
- DAn ampere rating matching the branch-circuit breaker, without checking horsepower
Where to look it up
https://docinfofiles.nfpa.org/files/AboutTheCodes/70/70_A2025_NEC_P11_FD_PIResponses.pdf
Why A is correct
This motor controller needs a horsepower rating no lower than the motor’s rating at the application voltage. Read the controller’s marked rating for that voltage; a branch-circuit breaker’s ampere rating is not the controller horsepower rating. Source: unchanged 2023 baseline in NFPA Public Input 1786, PDF page 98 (printed 78). https://docinfofiles.nfpa.org/files/AboutTheCodes/70/70_A2025_NEC_P11_FD_PIResponses.pdf