Romex NMB in crawlspace?

Status
Not open for further replies.
So, our local residential inspector claims Romex is not allowed in a crawlspace due to the 2014 NEC.
I believe I've read information contradicting this.

I thought a crawlspace was considered a potentially damp and not necessarily wet location. This of course may depend on the flood elevation. Which there are many flood zones in my area.

If a home were well above flood plane, is NMB suitable for use in a crawl per 2014 code?
 
Last edited:

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
A crawlspace should be designed so as to be kept dry. Otherwise mold will form.

I agree. I don't understood why so many people think a crawl space is a damp area. A little musty smell does not make an area "damp".

If it is indeed "damp" it is a design deficiency in the building, not an issue for the NEC.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I agree too, the crawl space should be a dry location.
It should be dry but I have seen many an old crawl space that was dripping wet from condensation on the duct work. I do agree , however, that it should be considered dry and I seriously doubt any moisture in the crawl will ever cause an issue with nm cable.
 

jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
Is this crawl space completely surrounded on all four sides by a wall? Concrete or other material?

Also is the floor above it watertight? If this crawl space is under a deck where water can collect and seep through the cracks, it's a wet location.
 

jaylectricity

Senior Member
Location
Massachusetts
Occupation
licensed journeyman electrician
Then I agree with everybody else. Ask him to cite the article violation by saying you want to read the article and figure out the best way to comply. If he says it's a local thing ask him where you can read the local amendments. If he can't do both of those things, you have enough ammo to stand your ground.
 

bphgravity

Senior Member
Location
Florida
So, our local residential inspector claims Romex is not allowed in a crawlspace due to the 2014 NEC.

If Type NM Cable is not intended to be installed in a crawlspace, you wouldn't need the language in Section 334.15(C). I think that clearly indicates Type NM cable can be installed in crawlspaces.
 

SMHarman

Member
Location
NYC
I agree. I don't understood why so many people think a crawl space is a damp area. A little musty smell does not make an area "damp".

If it is indeed "damp" it is a design deficiency in the building, not an issue for the NEC.
Indeed the musty is static air more than damp. Like grandma's closet.

Sent from my LT26i using Tapatalk
 

JFletcher

Senior Member
Location
Williamsburg, VA
So, our local residential inspector claims Romex is not allowed in a crawlspace due to the 2014 NEC.
I believe I've read information contradicting this.

I thought a crawlspace was considered a potentially damp and not necessarily wet location. This of course may depend on the flood elevation. Which there are many flood zones in my area.

If a home were well above flood plane, is NMB suitable for use in a crawl per 2014 code?

I know this post is 5+ months old, however the inspector's argument based on the 2014 NEC is in err; VA is on the 2012 VA Residential Code, not the 2014 NEC. Other applications fall under the 2011 NEC, again, not the 2014.

Anyway, my questions re: crawlspaces as possible damp locations are these:

1) If, during construction, the crawlspace is damp (moisture dripping from everything: ductwork, pipes, framing), would it being a damp location at the time of install of NM be a code violation? How long are 'temporarily wet/damp' are dry locations allowed to be so?

2) The Chapter 1 definition of damp leaves a bit to be desired: I'm reading it as 'humid enough to cause condensation'. Is this basically correct? I ask because installing dehumidifiers in crawlspaces is done very often here, even in homes that have ventilated crawlspaces. What has to be damp for a location to be classified as such: the ceiling, the walls, the floor, equipment??? and if it were determined that a particular crawlspace were a damp location, would a dehumidifier render it a dry one (code-wise)?

OP is from VA Beach, which as it name might imply, is close to/at sea level, and with a high water table. Here (50 miles away) we are much the same, just on the river and not the ocean. It is also very humid here many months of the year, and condensation in crawlspaces isnt uncommon (basements are uncommon due to the aforementioned high water table), especially in the summer with central heat/air: there is enough cooling loss in most ductwork to drop the air temperature below the dew point to get moisture.

Are there any areas of the country where local/state code forbids NM in crawlspaces?
 

jap

Senior Member
Occupation
Electrician
I know this post is 5+ months old, however the inspector's argument based on the 2014 NEC is in err; VA is on the 2012 VA Residential Code, not the 2014 NEC. Other applications fall under the 2011 NEC, again, not the 2014.

Anyway, my questions re: crawlspaces as possible damp locations are these:

1) If, during construction, the crawlspace is damp (moisture dripping from everything: ductwork, pipes, framing), would it being a damp location at the time of install of NM be a code violation? How long are 'temporarily wet/damp' are dry locations allowed to be so?

2) The Chapter 1 definition of damp leaves a bit to be desired: I'm reading it as 'humid enough to cause condensation'. Is this basically correct? I ask because installing dehumidifiers in crawlspaces is done very often here, even in homes that have ventilated crawlspaces. What has to be damp for a location to be classified as such: the ceiling, the walls, the floor, equipment??? and if it were determined that a particular crawlspace were a damp location, would a dehumidifier render it a dry one (code-wise)?

OP is from VA Beach, which as it name might imply, is close to/at sea level, and with a high water table. Here (50 miles away) we are much the same, just on the river and not the ocean. It is also very humid here many months of the year, and condensation in crawlspaces isnt uncommon (basements are uncommon due to the aforementioned high water table), especially in the summer with central heat/air: there is enough cooling loss in most ductwork to drop the air temperature below the dew point to get moisture.

Are there any areas of the country where local/state code forbids NM in crawlspaces?


If your roll of NM gets rained on in the back of the truck between the supply house and the jobsite is it a code violation to install it? :)

JAP>
 

kwired

Electron manager
Location
NE Nebraska
If your roll of NM gets rained on in the back of the truck between the supply house and the jobsite is it a code violation to install it? :)

JAP>
Been debated here before, some say yes others say no.

Personally if it were my home and it were damp enough in the crawlspace to cause condensation issues - I would have more concerns then just the wiring methods used in there, NM cable likely outlasts other potential issues in there, my number one concern is mold.
 
Status
Not open for further replies.
Top