Enclosure Question

[Jraef]

That is the ANSI standard for enclosure types. However the certification to the NEMA standard is a self certification, like with a CE certification. If the product is required to be listed it would have to be certified by a NRTL.

UL took over the NEMA enclosure specs (now UL-50) and testing as part of the listing process years ago. I try not to use the term "NEMA" for enclosure types any longer, because the term "NEMA" was not dependent on testing and listing by anyone other than the manufacturers. Some schlocky foreign suppliers were duping people into buying boxes that THEY claimed were "NEMA 4", but were in fact IEC type IP55 and not UL listed at all, or only UL listed as Type 1! NEMA was just too toothless as a spec.

Drilling and tapping would only apply to something like Type 7 and 9 explosion proof. There is nothing to tap in a sheet metal enclosure. You need a hub or fitting that meets or exceeds the environmental rating of the enclosure when you need a penetration of any sort (conduit or cable gland etc.).