NM in conduit underground?

[mlnk]

Is it Code legal for NM-B to be installed in conduit underground? I assume that NM-C or UF would be permitted in conduit.

 

[iwire]

NM-B, no.

NM-C, no. (That is for damp, not wet locations)

UF, yes.

 

[iwire]

300.5 Underground Installations.


(B) Wet Locations. The interior of enclosures or raceways
installed underground shall be considered to be a wet location.
Insulated conductors and cables installed in these enclosures
or raceways in underground installations shall be
listed for use in wet locations and shall comply with
310.8(C). Any connections or splices in an underground
installation shall be approved for wet locations.

 

[jwelectric]

334.10 Uses Permitted.
(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)

(2) In outside and inside walls of masonry block or tile
(3) In a shallow chase in masonry, concrete, or adobe protected against nails or screws by a steel plate at least 1.59 mm (

in.) thick and covered with plaster, adobe, or similar finish

 

[augie47]

FWIW, the only NM-C cable I ever saw was also UF listed.