NM cable (romex) in PVC

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relochris

Member
Location
North Carolina
Over the years, I've run romex in PVC to run up to disconnects and panels. Until yesterday all inspectors have said it was fine. We scoured the NEC and couldn't pinpoint the article that disallows it. I did find 334.15(B) which says it's allowed to protect the cable from physical damage (SCH80 PVC). Anyone know where it states that this is not allowed? We were thinking maybe it was the part that excludes it from use in damp locations. :confused:
 

relochris

Member
Location
North Carolina
This particular inspector is like the gestapo. I've found it's just best to do as he says. We ran a 10-2 romex through the crawl space. We punched out of the foundation with a piece of 3/4 pvc(sch40) into an LB and piped up about 2 1/2 feet up to a pullout disconnect for the AC. He said that sheathed cable cannot be run in conduit. He also said that he would have accepted it if it were UF. Seemed kind of contradictory to me.
 

iwire

Moderator
Staff member
Location
Massachusetts
This particular inspector is like the gestapo. I've found it's just best to do as he says. We ran a 10-2 romex through the crawl space. We punched out of the foundation with a piece of 3/4 pvc(sch40) into an LB and piped up about 2 1/2 feet up to a pullout disconnect for the AC. He said that sheathed cable cannot be run in conduit. He also said that he would have accepted it if it were UF. Seemed kind of contradictory to me.

In this case it has to do with wet locations, running NM in a conduit outside is a violation, running UF in the same conduit is not.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
2008 NEC 334.10(A)(1) "For both exposed and concealed work in normally dry locations except as prohibited in 334.10(3)."

And:
Article 100
Location, Wet.
Installations underground 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.
The Handbook goes on to say: "The inside of a raceway in a wet location and a raceway installed underground are considered wet locations. Therefore, any conductors contained therein would be required to be suitable for wet locations."
 

iwire

Moderator
Staff member
Location
Massachusetts
To add to Al's post.


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.


300.9 Raceways in Wet Locations Above Grade. Where
raceways are installed in wet locations abovegrade, the interior
of these raceways shall be considered to be a wet
location. Insulated conductors and cables installed in raceways
in wet locations abovegrade shall comply with
310.8(C).
 

glene77is

Senior Member
Location
Memphis, TN
In this case it has to do with wet locations, running NM in a conduit outside is a violation, running UF in the same conduit is not.

iWire,

Right.
Some time back, I was in a thread I had started as a joke,
with a picture as a teaser.
I had Romex coming out of a conduit, from the ground into a control box.

So, in the end, the consenus was that the NM-B had paper filler
which would / could wick the conduit's moisture up into a control box.
UF cable does not have this paper filler.
THHN plulled into conduit does not have a wicking agent.

NEC rules circumvent this potential problem,
by simply disallowing use of Romex in a non-dry environment,
such as conduit run outside or underground.
 

jxofaltrds

Inspector Mike®
Location
Mike P. Columbus Ohio
Occupation
ESI, PI, RBO
It is a damp location not a wet location.

The handbook under Location, Wet takes you to Article 410.4(A). Where is Article 410.4(A)? It is not in the handbook.
 

kwired

Electron manager
Location
NE Nebraska
This particular inspector is like the gestapo. I've found it's just best to do as he says. We ran a 10-2 romex through the crawl space. We punched out of the foundation with a piece of 3/4 pvc(sch40) into an LB and piped up about 2 1/2 feet up to a pullout disconnect for the AC. He said that sheathed cable cannot be run in conduit. He also said that he would have accepted it if it were UF. Seemed kind of contradictory to me.

NM not allowed in wet location like others said. UF is still a sheathed cable. Maybe this inspector needs to quote you the code sections you are in violation of instead of just making it up. (He was right, but for the wrong reasons).
 

jxofaltrds

Inspector Mike®
Location
Mike P. Columbus Ohio
Occupation
ESI, PI, RBO
This particular inspector is like the gestapo. I've found it's just best to do as he says. We ran a 10-2 romex through the crawl space. We punched out of the foundation with a piece of 3/4 pvc(sch40) into an LB and piped up about 2 1/2 feet up to a pullout disconnect for the AC. He said that sheathed cable cannot be run in conduit. He also said that he would have accepted it if it were UF. Seemed kind of contradictory to me.

I do not think that this meets a wet location. I think it is damp.

300.9 says "where raceways", it does not say that 'all' raceways are to be concidered wet.

Really does not matter NM not allowed.

The hanbook says that there is a 410.4(A). 410.4(A) is not in the handbook.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
What if you strip back the NM to a point where the conduit is in a very dry installation?
Are the coductors themselves of the type that normally would be permitted.

Just curious.

Wicking:
I see the issue with the wicking of the paper. I just had a repair where there was a very small leak in a wall. The water ran through the hole in the top plate, down the wire into the box. The NM appeared to be stripped with a box knife and sliced the insulation of the Hot. The wet paper conucted curent which created heat and melted the wires. It even caused enough heat that a wire under the same staple passing by the outlet box melted through and shorted also. It was very weird to troubleshoot. You had two unrelated shorts ( so it seemed) the second of which whoes wire should not have even been in that area.

Go figure.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
I do not think that this meets a wet location. I think it is damp.

300.9 says "where raceways", it does not say that 'all' raceways are to be concidered wet. ...

So are you telling us this raceway that is installed on the outside wall of the building is not in a wet location?
 

iwire

Moderator
Staff member
Location
Massachusetts
I do not think that this meets a wet location. I think it is damp.

300.9 says "where raceways", it does not say that 'all' raceways are to be concidered wet.

Really does not matter NM not allowed.

The hanbook says that there is a 410.4(A). 410.4(A) is not in the handbook.

I am definitely lost in what you are saying.

If the raceway is installed a wet location the inside of the raceway is also a wet locations, there is no gray area since the addition of 300.9
 

haskindm

Senior Member
Location
Maryland
What if you strip back the NM to a point where the conduit is in a very dry installation?
Are the coductors themselves of the type that normally would be permitted.

Just curious.

What does the marking on the conductors inside an NM sheath say? Answer, nothing. It is not marked, so we do not know where they can be installed. Look at 310.8(C). These are the types of wires that must be used in wet locations. Do you know what type of insdulation is on the conductors in type NM. UF comes under (C)(3) in that the assembly is listed for use in wet locations.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
What does the marking on the conductors inside an NM sheath say? Answer, nothing. It is not marked, so we do not know where they can be installed. Look at 310.8(C). These are the types of wires that must be used in wet locations. Do you know what type of insdulation is on the conductors in type NM. UF comes under (C)(3) in that the assembly is listed for use in wet locations.

I think this was debated elsewere about the wire in a NM cable. Looking at southwire specs it is:
Southwire's Romex SIMpull ? Type NM-B cable is manufactured as 2, 3, or 4 conductor cable, with a ground wire. Copper
conductors are annealed (soft) copper. Stranded conductors are compressed stranded. Conductor insulation is 90?C-rated
polyvinyl chloride (PVC), nylon jacketed. Southwire's SIMpull ? Designed for Easier Pulling, Resulting in Easier installation.
The cable jacket is color-coded for quick size identification; White - 14 AWG, Yellow - 12 AWG, Orange - 10 AWG, and Black -
8 AWG and 6 AWG.

I belive that was the same type of insulation they used in the old THHN before the simpull. I wonder why they just don't make a non-paper type NM. ( not UF too tuff to use generally) It is my understanding the paper is the whole problem when using NM to be sleeved a short distance. The nex thing we will be told is that we cannot use NM to wire a outdoor wall sconce even if the box opening is flush with the wall.


 
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