NEC Section 430.8 requires specific marking on motor controllers. Motor controllers can be large and elaborate or something as simple as the manual motor control switch in the image.

Motor controllers are required to be marked with the manufacturer’s name or identification, the voltage, the current or horsepower rating, the short-circuit current rating (SCCR), and other data necessary to properly indicate the applications for which it can be used.

It is interesting how the NEC^® emphasizes that the SCCR value of the motor controller is necessary data so that the suitability of the controller can be determined.

In order to comply with NEC^®, 110.9 and 110.10, the Available Fault Current (AFC) would need to be determined where the motor controller is installed. If the motor controller in the image was installed on the load side of a circuit breaker rather than a fuse, the installation would violate NEC^® 110.10 since the motor controller in the image only has a SCCR when protected by specific types of fuses.

See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on the “free access” tab and select the applicable year of NFPA 70 (National Electrical code).

2014-2017 Code Language:

430.8 Marking on Controllers. A controller shall be marked with the manufacturer’s name or identification, the voltage, the current or horsepower rating, the short-circuit current rating, and other necessary data to properly indicate the applications for which it is suitable.