Code Change Summary: A new code section regarding screws and fasteners used with cabinets, cutout boxes and meter socket enclosures.

All too often, a screw is dropped into the abyss when removing the cover from a panelboard cabinet, cutout box, or meter socket enclosure. When reinstalling the cover, a drywall screw or whatever is available ends up being used in place of the missing screw. The electrician typically turns his head slightly away with a slight cringe on his face while driving the screw as he hopes he won’t hear a loud pop.

If the description above sounds familiar, then the reason for the following 2023 code change will come as no surprise.

In the 2023 NEC^®, Section 312.10 was added to make sure the above scenario no longer takes place. This new code change requires the following:

Field installed screws or other fasteners that enter wiring spaces of cabinets, cutout boxes, and meter socket enclosures shall be provided by or specified by the manufacturer or must comply with the following as applicable:

(1) Screws shall be of the machine type with blunt ends.

(2) Other fasteners used must have blunt ends.

(3) Screws or other fasteners shall extend into the enclosure no more than 1⁄4 inch unless the end of the screw is protected with an approved means.

Exception to (3): Screws or other fasteners are permitted to extend into the enclosure not more than 7⁄16 inch if the screw or fastener is located within 3⁄8 inch of an enclosure wall.

Keep in mind that replacing the factory supplied screws with something else for a listed “Enclosed Panelboard” could present a problem. The Short Circuit Current Rating (SCCR) of an Enclosed Panelboard is verified with the factory screws installed and torqued as specified. These panelboard enclosures are tested for the containment of arcs and sparks and often found suitable for use where the available fault current is greater than 10,000 amps. When using screws for the cover, other than the screws provided by the factory, there is no guarantee that the enclosure will be suitable to properly contain arcs and sparks and carry fault currents greater than 10,000 amps during a fault condition.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC^® edition of NFPA 70.