Industrial electrical control panels are required to be marked with an SCCR rating. Prior to this, panel manufacturers only had to supply the interrupting rating of the panel overcurrent protective device, or the amperage at which the main disconnect to the panel would “trip”.

This means that since the 2005 NEC and UL508a release, industrial control panel manufacturers had to start not only calculating SCCR ratings for their panels, but also understand the available short-circuit current that is supplied at the customer facility where installation of the panel will be.

If the available short-circuit current supplied to the panel is higher than the SCCR rating marked on the UL508a label in the panel, installation of the panel is prohibited by NEC, 670.5. This requires industrial machinery electrical panel installers to verify the available fault current at their customer facilities.