NM-B vs UF for well pump

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fastline

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Location
midwest usa
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Engineer
We have both of these and would like to use it up and have a well pump install to do which will be in NM conduit in a trench. I can get THWN, which is what we usually would use, but.....

I recall NM-B as damp use but then not accepted in a sealed underground conduit? I know I have seen it in installs but that doesn't make it "right"....

We will need 12-2 for this install.
 
Underground is always a WET area and NM is not rated for wet areas. There's no such thing as a "sealed" conduit. I've watched gallons of water pour out of our "waterproof" conduits.
 
fastline said:
We have both of these and would like to use it up and have a well pump install to do which will be in NM conduit in a trench. I can get THWN, which is what we usually would use, but.....

I recall NM-B as damp use but then not accepted in a sealed underground conduit? I know I have seen it in installs but that doesn't make it "right"....

We will need 12-2 for this install.
Click to expand...

NM is only good for dry locations. I assume you are a well pump installer... If you install nm in conduit in a wet environment it would not be compliant. Underground is a wet location...
 
No, I usually don't mess with this too much anymore but I mainly ask because I recall an inspector saying "if it's gray, it can stay".... I think his reference was to UF-B, but we happen to have some gray NM, which I think is pretty damn old and I have never seen gray NM before. I know I have opened the cap of well pumps to see paper in the cable. How it gets signed off is beyond me.

Thanks for the code references.
 
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