There is not a lot of enlightenment in the reference to UL STD 2239.
Also from the spec's wording:
Maximum distance between each CC under floor joists is 16″ (when using under floor joists, the maximum distance, on one side from any wall, joist, pipe or ductwork is 12″)
I can't find a reference in NEC 334 to any 12" requirements for wall, joist, pipe or ductwork. I wonder where that came from.
Running boards won't offer protection from Harry putting up that ceiling. I always thought this was about discouraging him from hanging things from the cables.
You can still hang your laundry from a cable running through bored holes. I haven't been able to find the ROP for that rule to see the logic tho. It seems to be a very old rule. 336-8 in the 68 code is the same.
Nice brackets. For entertainment I’ve attached a picture of what I did in a similar situation.
On point: I understand the tortured code language to be referring to an assumption that joists will not be more than 24” on center. Should they be farther apart, additional support is needed.
The last time code panels addressed basement cables, the main concern was folks hanging stuff from them, or snagging them as they moved about. This was not seen as an issue if the cables were within the space between the joists. There, I presume, the general 48” support spacing is good enough.
The “hanging” concern is real. Somewhere on this site is a picture I took decades ago of the 1” EMT feeding a sub panel being used as the clothes rod for a locker room by the laundry service.
