Which factor is used to determine the maximum size of a standard overcurrent device for a motor when multiple data points are provided on the nameplate?

Which factor is used to determine the maximum size of a standard overcurrent device for a motor when multiple data points are provided on the nameplate?

• A. The color of the enclosure
• B. The horsepower rating
• C. The FLA and code letter
• D. The voltage alone

Answer: (C)

The important idea is that motor protection is based on data that reflects how the motor behaves, not just its size or voltage. On the nameplate, you’ll find the full-load current (FLA) and a code letter. The FLA tells you the running current, while the code letter encodes the motor’s starting current and thermal characteristics. NEC rules use both pieces of information together to determine the maximum size of the standard overcurrent device (breaker or fuse) that can protect that motor circuit. Horsepower, voltage alone, or the enclosure color don’t capture the motor’s inrush behavior or thermal response, so they aren’t enough by themselves.

The important idea is that motor protection is based on data that reflects how the motor behaves, not just its size or voltage. On the nameplate, you’ll find the full-load current (FLA) and a code letter. The FLA tells you the running current, while the code letter encodes the motor’s starting current and thermal characteristics. NEC rules use both pieces of information together to determine the maximum size of the standard overcurrent device (breaker or fuse) that can protect that motor circuit. Horsepower, voltage alone, or the enclosure color don’t capture the motor’s inrush behavior or thermal response, so they aren’t enough by themselves.