NM run throughPVC

[al hildenbrand]

Al are you telling me that NM can't be used in PVC because it will get wet or be subect to excessive moisture or dampness. I am just trying too understand 334 better.

Right. The uses prohibited includes wet locations. Other areas of the Code tell us about wet locations.

300.5 Underground Installations

(B) Listing Cables and insulated conductors installed in enclosures or raceways in underground installations shall be listed for use in wet locations.

Article 100 Definitions

Location, Wet. Installations under ground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.

 

[guschash]

So then NMC would be ok too use, not that you would want to pull it through PVC but you could, right.

 

[George Stolz]

The key in my mind is:

300.5 Underground Installations

(B) Listing. Cables and insulated conductors installed in enclosures or raceways in underground installations shall be listed for use in wet locations.

A cable installed inside a raceway installed underground shall be listed for wet locations.

NM cable is not listed for wet locations, so no matter how dry you keep that underground raceway (if hypothetically it could be done), it would still be against code.

 

[George Stolz]

So then NMC would be ok too use, not that you would want to pull it through PVC but you could, right.

No, see 334.10(B):

(B) Type NMC. Type NMC cable shall be permitted as follows:
(1) For both exposed and concealed work in dry, moist, damp, or corrosive locations, except as prohibited by 334.10(3)

A wet listing is more wet than "dry, moist, damp".

 

[guschash]

Ok thanks. I appreciate the help in trying to understand the code.

 

[George Stolz]

I sure hope it blew your mind the way it did mine, when they first told me!

 

[iwire]

You could however pull UF cable in conduit underground.