We have some Romex wiring in the unfinished section of our basement
which runs at right-angles to the joists above. It is secured with
staples on the bottom of the joists, which I understand to be against
code for wire sizes less than 6-2 or 8-3. I have a few questions
relating to this situation, and would be grateful for some guidance...
1/ I understand that if I install running boards, the Romex can be
stapled to those, and everything will be code. Would it be sufficient
for this boards to go between the inside faces of the joists, perhaps
affixed with pocket hole screws in their ends, or must they actually
run below the bottom of the joists? Also, since code only demands
stapling to the running boards every 4 feet or so, how does this
provide any more support than stapling to each joist, given that the
joists are considerably closer than 4 feet?
2/ Would it also meet code to cover the wiring, perhaps with some sort
of partial plywood ceiling, mounted on but spaced away from the
joists? This would ensure that the wiring would be inaccessible, but
I'm not sure it would remove the requirement for no stapling.
3/ How long has the no-staples rule been around? All this wiring was
done by reputable licensed electricians, as far as I can tell, and so
was it installed prior to this rule being established? Or the rule
more honored in the breach than the observance?
4/ Why exactly is this rule in place? I've read a couple of theories,
namely that it is to prevent sagging of the cables, or that it is to
prevent people hanging things on them. The first seems strange, as
stapling to each and every joist provides more support than would be
provided, say, by stapling every 4 ft or so on a running board. And if
the second theory is correct, simply blocking off access would avoid
As I say, any comments would be welcome.