Re: Attic Spaces, 320.23
When running type NM through a residential attic I only run it crosswise and on top of the joists where the headroom is less than enough to stand. I also avoid running crosswise in the center area where I would have to walk to fix attic fans or where people could store stuff. I have done quite a bit of monkeying around in attics that have no floor or least enough monkeying to know that some Code rules are bogus.
An example of a bogus rule is how deep a 480 volt streetlighting conduit needs to be underneath a public sidewalk. One time USA Today installed a vending machine and drilled into a Cleveland Public Power 480 volt streetlighting conduit. Since the power was turned off by the central controller nobody noticed that they had done anything wrong. The next time it rained at night USA Today fatally toasted a customer. Cleveland Public Power was exonerated because the burial depth was "Code"!
There is also another issue is that the cheap trusses used in houses cannot be drilled when running cables crosswise so you MUST run them on top of the floor beams or the unside of the rafters.
An exception was that during the summer of 1988 someone had me wire a 5 car garage ( 5 door with one stall long enough for a motor home ) and he used extra strong trusses so that he could store lots of roofing business and vaction goods up in the attic, In this case, I could drill holes in the beams for the crosswise cables. The center was just high enough that the cables the the attic ceiling lights did not need to have running boards - if shorter I would have used EMT instead like I did where the cables went up from downstairs. Both ends had a permanent ladder and there was no drywall installed. The center row of downstairs lights was underneath the attic floor and the other 2 rows of dwonstairs lights were too far away from the center to worry about goods falling on the cables. Essentially, the 3 places where cables went crosswise through the floor either had protection inherently installed of did not need it.
I am also an opponent of using and attic and an outside wall as a Mickey Mouse cable tray that is filled with thermal insulation.
