NM

[dexterg]

Is it permissable to run romex underneath a house stapled to the floor joists ? , wouldn't that be considered a "damp location? I'm talking about a house that is on blocks or piers with a skirting around the perimiter. This has always kind of bothered me for whatever reason. It is common practice around here in Texas however. Give me some feedback please.

 

[infinity]

Here's what the 2011 NEC says about crawl spaces and NM cable, I have no opinion on whether or not it's a damp location.

(C) In Unfinished Basements and Crawl Spaces. Where
cable is run at angles with joists in unfinished basements
and crawl spaces, it shall be permissible to secure cables
not smaller than two 6 AWG or three 8 AWG conductors
directly to the lower edges of the joists. Smaller cables
shall be run either through bored holes in joists or on running
boards. Nonmetallic-sheathed cable installed on the
wall of an unfinished basement shall be permitted to be
installed in a listed conduit or tubing or shall be protected
in accordance with 300.4. Conduit or tubing shall be provided
with a suitable insulating bushing or adapter at the
point the cable enters the raceway. The sheath of the
nonmetallic-sheathed cable shall extend through the conduit
or tubing and into the outlet or device box not less than
6 mm (1⁄4 in.). The cable shall be secured within 300 mm
(12 in.) of the point where the cable enters the conduit or
tubing. Metal conduit, tubing, and metal outlet boxes shall
be connected to an equipment grounding conductor complying
with the provisions of 250.86 and 250.148.

 

[Dennis Alwon]

Is it permissable to run romex underneath a house stapled to the floor joists ? , wouldn't that be considered a "damp location? I'm talking about a house that is on blocks or piers with a skirting around the perimiter. This has always kind of bothered me for whatever reason. It is common practice around here in Texas however. Give me some feedback please.

Don't lose sleep over it. Technically it could be argued that NM cable is not listed for those locations, however, I have seen nm in situation where water is dripping off the nm from condensation and has been like that for years. Never seen an issue with the cable either.

I think this is a situation that no inspectors wants to take on as it would be an incredible injustice to everyone involved.

 

[kwired]

This is a little like the argument whether NM cable is allowed to penetrate exterior wall to feed a light, receptacle or even a disconnect for A/C equipment. Once it penetrates the wall is it no longer allowed because it is a wet or damp location? Some say it is OK some say it is not. NEC does not address this application specifically.

 

[JDB3]

Jdb

Jdb

At a lake outside of Austin, Texas (back in the 70's) they had NM ran in the "water" to spider (floating, but anchored) docks.

 

[kwired]

The problem with NM is the paper lining is absorbent and can wick the water from one point to another. Individual conductors though not marked with a type are likely moisture resistant.

 

[mikeames]

Here's what the 2011 NEC says about crawl spaces and NM cable, I have no opinion on whether or not it's a damp location.

Yea but some house are on stilts like at the beach and I would not clasify that as a crawl space since you can park a car under it. Then again it then may be considered "outdoor" since technically it is.