[dgrider]

My home is insulated on the floor of the 2nd story crawl spaces with that spay-in insulation that looks like mouse nest. When re-wiring, several wires ( 12-2 NM-B ) will be in direct contact with this insulation while passing through the sole-plates.

It may also be in contact when running parallel with joists. I will also need to run some of the wiring under the floor of the second-story rooms between said joists, which will also submerge the cable in this insulation, although I may run this cable in conduit due to securing issues ( roughly 7-10 ft where I won't be able to reach the wire to secure with staples ).

Is "Romex" approved for contact with insulation. Would this be a fire hazard, or cause any overheating issues that would call for derating?

Thank you.

[tkrussell]

Romex has no restriction to being in contact with insulation. You can also fish or snake Romex and not need to worry about supporting.

If you were to run a bundle of cables together, whether in insulation or not, the cables would need to be derated.

The wiring that cannot be embedded in insulation is the old Knob & Tubing type. Maybe this is where you question is coming from?

[dgrider]

You can also fish or snake Romex and not need to worry about supporting.

Hmmm... I had intended to secure the wire as much as possible, be it vertical between-the studs runs or horoziontial runs between the joists. I believe the cable is supposed to be supported within 8-12" of the device box, but it was my feeling that this was not enough for the entire run up the wall into the crawl-space ( roughly 5ft from the outlet to sole-plate ). Are you saying that the support at the device box and the last support above the sole-plate would be sufficient?
I can see it not needing support just laying between the joists under the upstairs rooms... I'm just very anal about that sort of thing. I like to be neat, and assume the worst case scenario will happen.

As far as the insulation question and NM... I figured it was approved, just wanted to be sure. Better safe than sorry.

TK, your incredibly helpful. Thanks a ton.

[tkrussell]

If your fishing the cable through voids, no need to support the cable.