On Aug 11, 10:21*am, Wayne Whitney wrote:
On 2010-08-11, wrote:

The easiest, direct run would be to use the rafters and the run would
be perpendicular to them. * *Is it permissible to just staple to the
underside of the rafters or do you need to nail a furring strip and
then staple to that?

Actually, you nail the furring strip alongside the cable. *

2008 NEC 320.23(A) in part: "Where run across the top of floor joists,
or within 2.1 m (7 ft) of floor or floor joists across the face of
rafters or studding, in attics and roof spaces that are accessible,
the cable shall be protected by substantial guard strips that are at
least as high as the cable."

Thanks for the help Wayne and the cite. A follow on question:


They use the term "guard strips". Does that mean one strip on each
side of the cable or is just one along one side it sufficient? For
example, if the cable is running perpendicular to the rafters and I
staple the cable say 5 ft off the floor, then nail a furring strip
uphill of it on the rafter is that sufficient? The bottom side where
the cable is would then be fairly inaccessible.

Also, without the cable being attached to the furring strip, I guess
the strip has to be high enough so that the cable can't sag enough
between rafters to stick out beyond it. What would normally be used,
something about 3/4" thick?



The cross members are spaced many feet apart, probably 4X the
distance between rafters, and the romex is unsupported in between.

The romex should be supported every 4.5' (NEC 334.30).

It looks like they can run the romex perpendicular across the tops of
those cross members because the tops of the cross members may be 7ft
above the floor.




Also, are there any special rules about clearance between Romex and
the furnace? *The easiest path would probably put it about 3 feet
above the furnace.

No problem.

Wayne