UL 508A Frequently Asked Questions

Q. How do you determing the rating of a branch motor circuit when the circuit breaker, contactor, and overloads are manufactured by different manufacturers?

A. Basically, it’s a common problem. You need to either look at the markings on each of those devices to determine which component has the lowest level and assign that value to the line side of the branch circuit protective device or go to the UL website to look at the combinations that have the higher fault rating

Category: Application

Keywords: branch circuit, motor controller, overlaod, contactor, circuit breaker, protective device