What’s Wrong Here? Hint: Too Close for Comfort

The roofer is using screws that are too long. The box is in fact below the. 1 1/2" required by code.

The boxes and the EMT should had been installed on unistrut at least 1-1/2 deep.

I agree with one of the respondants above that it certainly appears like the boxes and conduit are more than 1-1/2" below the deck. Appear to be mounted on I-beam type supports.

The conduit, and boxes are mounted directly to the roof pans( note the 1-hole strap on the conduit at the bottom of the picture), and none of the other conduits appear to be secured as required

Previous NEC editions have required protection of conductors where subject to physical damage. While most Code users understand this rule is intended to apply to all conductors in all wiring methods, it didn’t clearly state that. The 2011 revision clarifies that all conductors in all wiring methods must be protected from physical damage [300.4].

The rule in 300.4(E) regarding protection for raceways installed under metal-corrugated sheet roof decking has been expanded. The 2008 NEC introduced a requirement for the protection of most raceways when installed within 1½ in. of the underside of the roof deck. Although this 2008 rule change went a long way toward protecting wiring systems from damaging roofing screws that can penetrate the raceways, it left out one critical part of the installation — boxes. The 2011 revision corrects that and also clarifies that the measurement is to be made to the top of the cable, raceway, or box from the lowest surface of the roof decking (Fig. 1).

There would also be a concern if the existing conduit 110volt octagon box would be used for an incandescent light bulb and would effect the working ability of the heat detector installed within source distance of the device. Activation would occur creating false alarms and system could be affected by eddy currents or magnetic induction from the nearby electrical system mounted too close to the fire system.