Amend NEC^® 2017, page 266:

(B) Documentation. Deleted.

ELR commentary: This section is all about industrial control panels and making sure that they are properly rated for the available fault current at their location.

An “industrial control panel” can be factory made and very elaborate or something as simple as two lighting contactors, field installed in a large junction box. Article 100 defines an Industrial Control Panel as an assembly of two or more components consisting of one of the following:

(1) power circuit components only, such as motor controllers, overload relays, fused disconnect switches, and circuit breakers;

(2) control circuit components only, such as push buttons, pilot lights, selector switches, timers, switches, and control relays;

(3) a combination of power and control circuit components. These components, with associated wiring and terminals, are mounted on, or contained within, an enclosure or mounted on a subpanel.

In the 2017 NEC^®, Section 409.22(B) requires the following:

(B) Documentation. If an industrial control panel is required to be marked with a short-circuit current rating in accordance with 409.110(4), the available short-circuit current at the industrial control panel and the date the short-circuit current calculation was performed shall be documented and made available to those authorized to inspect the installation.

According to NEC^® 409.22(A), an industrial control panel shall not be installed where the available “short-circuit current” or available fault current (AFC) exceeds its short-circuit current rating (SCCR). The only way to ensure that the industrial control panel is not installed at a location where the available short-circuit current is higher than the control panels SCCR is to perform a calculation to determine the AFC at the control panel.

409.22(A) and (B) help to bring everything in compliance with NEC^® 110.10. Knowing the amount of short-circuit current available at the industrial control panel is the first step in selecting the right control panel. For example, if a calculation is performed and it is found that the amount of short-circuit current available at a control panel is 4,638 amps, then installing an industrial control panel with a short-circuit current rating of 5,000 amps is code compliant with NEC^® 110.10.

In North Carolina, 409.22(B) was deleted, yet 409.22(A) was not. It seems very backwards to require the industrial control panel to be installed per 409.22(A) which requires the control panels SCCR to be equal to or greater than the AFC at the control panel, but yet not be required to perform the AFC calculation in 409.22(B) in order to determine if compliance with 409.22(A) has been achieved.

Special note:

The North Carolina amendments did not change NEC^® 110.9 or 110.10 which are still enforced. Even though the AFC at the industrial control panel is not required to be documented in North Carolina, it must still be calculated in order to ensure compliance with 409.22(A), 110.9 and 110.10.