Wet/ damp location?

[nizak]

I have some PVC conduits that I installed under a basement slab at a new build.

They will be used as sleeves to get wiring to some island areas that are located in a finished basement.

If using NM cable, does it still have to be type UF since both ends of the sleeve terminate in interior areas that have consistent temperatures of 70 or so degrees?

 

[augie47]

IMO, based on 300.5, if the PVC is underground the interior will be a wet location and NM would not be permitted. UF, or a wiring method approved for a wet location would be required regardless of the conduit termination locations

 

[mwm1752]

If the conduits are embedded in earth -- wet location

 

[mwm1752]

some slabs have infloor heat & insulation as a barrier between earth & conduit -- or a radon barrier that the conduit is on top of then IMO the conduit is not in a wet location

 

[infinity]

Conduit under or in slabs on grade are considered to be in wet locations.

Location, Wet. Installations underground or in concrete
slabs or masonry in direct contact with the earth; in loca-
tions subject to saturation with water or other liquids, such
as vehicle washing areas; and in unprotected locations ex-
posed to weather

 

[K8MHZ]

Conduit under or in slabs on grade are considered to be in wet locations.

If in direct contact with the earth.

It seems if the slab and conduit was on top of a plastic sheet it would not be in direct contact with the earth, as mentioned before.

 

[macmikeman]

I don't have any problems with the locations in the NEC designated for Wet Locations. It is the Damp Locations definitions that I disagree with. They should make it into two categories, Damp locations and Really Damp Locations and allow some common sense to dictate conditions based on actual conditions........