Got to disagree.
That is why I have two titles:
Inspector & SOB. I think the second one is something about Same Old...
First, stud and joist spaces are connected to the plenum / duct system and are definately part of the 300.22(B) space. If you check the exception to 300.22 (C) the reason for the exception is because it is not to be considered anything other than a duct as covered by 300.22 (B)
Regular NM cable is allowed to run across a space in 300.22 (B). It is done all the time.
NM cable is not allowed to run the length of a 300.22 (B) space nor is a junction or device box allowed in that space unless designed for use in a duct or plenum.
The other space 300.22 (C) is for above ceiling areas and rooms that may have furnaces in them because some inspectors did not allow a return air grill on a furnace unless the entire room was wired as a plenum. That was overkill.
I do not allow any [except dust tight] junction boxes or device boxes in the stud or joist space used for return air. They trap dust and dirt in the boxes.
To solve the problem have the electrician {carpenter} put a length of 2X4 where the box is, from top to bottom with the top & bottom closed off and forget about any metal sleeveing on the cable. That way the box is no longer in the plenum / duct space.
Do not accept the tin foil cardboard as a substitute for the 2X4 as a way of getting the box out of the duct. The drywall can seal against the 2X4 with nails, the cardboard can not.
The 90' connector is still a violation, NM cable or not.
HVAC guys get it messed up all the time. One even insist that he always runs his thermostat wire inside the duct to get to the upstairs.
I have seen dust and dirt in boxes that resulted in fires.
Have your Code Panel respond to this at the next IAEI meeting. Or just ask Joe T.
Alan-- Inspector--
CEI-M #138 listed in the IAEI NEWS
