Romex in damp locations (crawlspace)

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Old 01-20-15, 04:18 PM
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Romex in damp locations (crawlspace)

I've just finished ripping the old knob&tube wiring out of my attic. There was an existing 2-pin outlet in the living room (front wall of the house; blue arrow/H in pics) that was fed from the attic and is now abandoned.

Floorplan:



I'm planning on rewiring using the existing circuit that runs in the unfinished crawl space under the living room. It's a 20A circuit running in conduit which terminates at a junction box where it feeds an outlet and then turns into NM which feeds two existing outlets ('o' symbols).

I right-angle drilled a hole through the sill (blue "H") to access the existing 2-pin on the front wall. I'm going to control it from a unused switch in a wall duplex so I drilled a hole to access that (red 'H'). I also want to add a new outlet on the living room outer wall (green 'H').

I was planning on extending the existing romex, going through the joists from the end outlet to the green 'H' (to avoid the RG6 stapled to the outside wall) then back along the outer wood frame above the foundation to blue 'H'.

My question is whether the location is too damp for Romex? You can see mold spores around the green location (yes I'm wearing a respirator).

There is foil stapled to the floor joists, I guess 1920's idea of insulation. So I'd be running the Romex under that and restapling it. Any problems doing this?









 
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Old 01-20-15, 06:25 PM
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Hard to tell. If in doubt you could use UF through drilled holes or on a running board.
 
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Old 01-20-15, 08:23 PM
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I'm not sure either. I'm only seeing (what I think are) mold spores in the area around the cold water pipe (in the final picture). There is a faucet on the other side of the wall.

I left off the original floorplan that there is a covered concrete porch that I think was added later. The porch starts between the green arrow and the cold pipe and continues left, so all of the areas where I drilled holes are actually behind the porch.

I couldn't see any area where there was obvious 'wetness' but clearly there is moisture in the area.

The dashed line is where I was planning on routing the new cable, through the joists (they run left-right) and then (left) along the running board above the foundation.




I've never used UF cable. There is blown in cellulose insulation in the walls. I assume it's safe for this.

Also I'm using these Arlington remodel boxes (http://www.aimedia.co/media/spec-sheets/F101.pdf) as the locations butt against a stud, standard knockout and they include snap in plastic NM clamps. I'm not sure if they would work with UF?

 

Last edited by dorkshoei; 01-20-15 at 08:58 PM.
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Old 01-21-15, 03:30 AM
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UF is a little harder to strip than NM, but otherwise is very similar and can be used in the same areas as well as damp and wet locations. The provided clamp will work.
 
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Old 01-21-15, 10:03 AM
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A few other threads I found googling:

http://www.doityourself.com/forum/el...awl-space.html (only useful comment is #2 then it degenerates into discussion of stapling to underside of joists; I'll be drilling)

NM or UF in crawlspace. - Electrical Wiring Forum - GardenWeb

Is Romex in a crawl space a problem? - InterNACHI Inspection Forum (this is probably the most interesting).

Based on this final thread I'm leaning towards just using NM (as I just bought it). If I didn't already have it, I'd get UF. The joists are all dry and I'll be stapling to them and drilling through them. The only area that is 'moist' is the ground under the plastic sheeting and that's several feet below where the wire will be located.
 
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Old 01-21-15, 10:59 AM
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I talked to city chief inspector; crawlspace in half/unfinished basement is not considered 'damp' location for them. As long as I don't install cable near to ground/plastic sheeting I can use NM all day long. Explained I would be drilling through joists and stapling to running board. I'm good to go.
 
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Old 01-21-15, 01:42 PM
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I almost posted that I would not consider a crawl space as unsuitable for type NM cable but it is good that you got the official word from your inspection office.
 
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Old 01-21-15, 06:17 PM
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I have seen crawls that I could swim in with a couple of inches of water to ones that were bone dry. All depends. Glad you checked with your inspector.
 
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