Industrial control panel markings and SCCR
Industrial control panels must carry permanent markings, including supply voltage and full-load current, the short-circuit current rating (SCCR), and the enclosure type. The SCCR must not be lower than the fault current available where the panel is installed.
What the code requires
Section 409.110 lists the markings an industrial control panel must carry. They must be permanent and still visible after installation. The supply information and the multiple-disconnect marking go on the outside of the enclosure; the other markings may be inside or outside.
The required markings are the manufacturer's name; for each incoming supply circuit, its voltage, phase count, frequency and full-load current; and, where the panel has more than one source and more than one disconnect is needed to de-energize all circuits of 50 V or more, a marking saying so, with documentation of where the disconnects are.
The panel must also show its short-circuit current rating, based on a listed and labeled assembly or an approved method, such as UL 508A Supplement SB. Other markings cover suitability as service equipment (if it is meant to be used that way), the wiring diagram or a reference to it, and the enclosure type number.
On the job
- A panel whose marked SCCR is lower than the available fault current where it is installed does not comply (see 409.22).
- If shutting off everything at 50 V or more takes more than one disconnect, look for that marking on the outside of the enclosure and for documentation of where each disconnect is.
Exceptions that matter
- Panels that contain only control-circuit components do not need an SCCR marking.
What changed in 2023
The 2023 NEC made the markings permanent and specified that the supply-circuit and multiple-disconnect markings go on the outside of the enclosure, while the others may be inside or outside.
Related sections
- NEC 409.22
- NEC 409.70
- NEC 110.10
- NEC 670.3
Where this comes from
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