UL 508A Frequently Asked Questions

Q. What is the largest size overcurrent protective device that can increase the SCCR of a 5kA contactor?

A. The 5kA contactor rating is based on the marked overcurrent protective device that is required to be upstream of the contactor to achieve the 5kA rating. Exceptions 1 and 3 of SB4.2.3 allows for the use of an equivalent overcurrent protective device however at the same 5kA rating. Therefore, there is no provision to increase the marked 5kA rating of a contactor.

Category: Application

Keywords: overcurrent, protective device, SCCR, contactor