Use of Type NM Cable in Conduit Outdoors
Question: I would like to run Type NM cable through my outside wall and run along the outside of the house to another location of the house and re-enter the home. If this Type Nm cable is installed in EMT (electrical metallic tubing) properly filled with compression coupling and connectors, is this code-compliant?
Answer: No, Type NM cable cannot be installed outside, regardless of the wiring method enclosing it. The installation is a damp or wet location.
Reference: 334.12(B)(4) not permitted in a wet or damp location, 300.9 Raceways in Wet Locations Above Grade. Where raceways are installed in wet locations above grade, the interior of these raceways shall be considered to be a wet location. Insulated conductors and cables installed in raceways in wet locations above-grade shall comply with 310.8(C).