This document summarizes guidelines for determining short circuit current rating (SCCR) for electrical equipment. It discusses:
- Upcoming 2017 NEC changes that will require marking or documenting the available fault current where equipment is installed.
- Methods for determining equipment SCCR, including considering the ratings of components, overcurrent devices, and whether current-limiting devices can increase component ratings.
- Basic guidelines for using current-limiting devices to increase SCCR, such as only being able to raise branch component SCCR, not feeder components or overcurrent device ratings.
- A 4-step process to calculate equipment SCCR by determining component and overcurrent device ratings and identifying the lowest rating.