When installed under metal-corrugated sheet roof decking, cables and raceways are permitted in concealed locations if they are at least how far from a structural support member?

The correct answer is based on the provisions in the National Electrical Code (NEC) regarding the installation of cables and raceways in concealed spaces, especially when under metal-corrugated sheet roof decking.

For cables and raceways to be safely installed in such locations, they must be kept a minimum distance from structural support members to prevent potential damage from fasteners or other connections made to the structural framework. This distance is specified as 2 inches.

By maintaining this clearance, installers ensure that there is less risk of physical contact between the electrical conductors and the metal components of the structure. This helps mitigate potential hazards, such as shorts or mechanical damage, thereby enhancing the safety and longevity of the electrical installation. Keeping installations at this distance also aligns with best practices for preventing interference and allowing for maintenance or future modifications without disturbing the structural elements.