NMC in basement vs. crawl space

[sfav8r]

According to 334.15 all exposed work must comply with 334.15 (a)-(c).

334.15(c) requires that NMC running at an angle to the joists, if smaller that 2-6awg or 3-8awg, must be drilled and run through the joists or with running boards.

This seems simple enough, but my question is, what exactly is "exposed?"

In a crawl space that is 24", do you need to drill or can you staple to the joists? If this is permissible, does anyone have a code reference?

It also leaves me wondering when does a crawlspace become a basement? I just estimated a job that has about 4 feet of clearance.

Thanks.

 

[websparky]

Re: NMC in basement vs. crawl space

Concerning crawl space vs. basement, the code makes no exceptions, they are treated the same.

 

[dillon3c]

Re: NMC in basement vs. crawl space

334-15(c)"in unfinished Basements" Doesn't say and-or crawspace.

[ May 23, 2004, 12:08 AM: Message edited by: dillon3c ]

 

[websparky]

Re: NMC in basement vs. crawl space

2002 NEC
Concealed. Rendered inaccessible by the structure or finish of the building. Wires in concealed raceways are considered concealed, even though they may become accessible by withdrawing them.

Exposed (as applied to wiring methods). On or attached to the surface or behind panels designed to allow access.

334.15 Exposed Work.
(A) To Follow Surface. The cable shall closely follow the surface of the building finish or of running boards.

(C) In Unfinished Basements. Where the cable is run at angles with joists in unfinished basements, 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.

2003 IRC
BASEMENT. That portion of a building that is partly or
completely below grade

The term "crawl space" is a slang term which helps describe a basement that is not at the usual height and is not defined in the codes.

 

[Guest]

Re: NMC in basement vs. crawl space

In California we have very few basements.

Almost every dwelling in CA is lacking a basement, but the wood frame floor ones that lack basements do contain a "crawl space". A synonym for crawl space is "unexcavated area". I guess once it's excavated it becomes an "unfinished basement"?

 

[iwire]

Re: NMC in basement vs. crawl space

Crawl Space: a low unfinished space under a floor or above a ceiling in a building that gives access to plumbing, wiring, and ductwork.

 

[sfav8r]

Re: NMC in basement vs. crawl space

just met w/inspector. Said no prob running across joists as lon as they're sccured every 4-1/2 feet. They do not consider the area "accessible" as it is only 24" and you have to crawl through a small access door to get to it.

I think this is a good call even though there may not be specific exclusion in the NEC, because it seems highly unlikely that these wires would be damaged.

FYI - Their rule of thumb for when a crawl space becomes a basement is whether or not the space could be "useable", even in the future. In the case where it is possible to use the "room" at a later date, they consider it accessible even if the space is ot currently being used.

thanks for your input.