UL 508A Frequently Asked Questions

Q. For drives (motor controllers) under 50HP, the table offers a rating of 5.0. How can I increase my overall panel SCCR value when I use drives?

A. Table SB4.1 are default SCCR component values for unmarked components. The selected drives would need to be rated for the desired panel SCCR rating or make use of the power transformer current limiting option in Section SB4.3 to limit the available short circuit current.

Category: Application

Keywords: drives, motor controller, SCCR, power transformer