When installed under metal-corrugated sheet roof decking, are cables, raceways, and enclosures allowed in concealed locations as long as they are at least 2 inches away from a structural support member?

The correct answer is that cables, raceways, and enclosures are not allowed in concealed locations under metal-corrugated sheet roof decking, regardless of their distance from a structural support member. This is primarily rooted in safety and accessibility concerns. When wiring is concealed under a roof deck, it can be difficult to access for inspection, maintenance, or in case of a fault.

Additionally, the integrity of the installation can be compromised if these components are placed in locations that may be affected by moisture or condensation, which are common issues with metal roofing systems. Therefore, strict regulations specify that wiring methods must be visibly accessible or adequately protected, ensuring that any potential issues can be readily addressed without compromising the integrity of the roof structure or the wiring itself.