NM in Raceway

[Towzzer]

Hi Everyone,

Brand new registering but been reading the forum for a month or so. My first question as I come out from the woodwork is regarding NM in a raceway. I pretty sure it's not allowed for more than 10 feet but what is the exact reason behind it. For example if someone asked me why shouldn't I do that, what would be the best response. Also if anyone knows the location in the nec that would be cool too.

-Towzzer (from a retail store you know)

 

[jwelectric]

Re: NM in Raceway

334.15 Exposed Work.
(B) Protection from Physical Damage. Cable shall be protected from physical damage where necessary by rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit, or other approved means. Where passing through a floor, the cable shall be enclosed in rigid metal conduit, intermediate metal conduit, electrical metallic tubing, Schedule 80 PVC rigid nonmetallic conduit, or other approved means extending at least 150 mm (6 in.) above the floor.

In the above section the only distance that I see is ?at least 150 mm (6 in.) above the floor?

342.22 Number of Conductors.
Cables shall be permitted to be installed where such use is not prohibited by the respective cable articles.

344.22 Number of Conductors.
Cables shall be permitted to be installed where such use is not prohibited by the respective cable articles.

358.22 Number of Conductors.
Cables shall be permitted to be installed where such use is not prohibited by the respective cable articles.

334.12 Uses Not Permitted.
(A) Types NM, NMC, and NMS. Types NM, NMC, and NMS cables shall not be permitted as follows:
(1) In any dwelling or structure not specifically permitted in 334.10(1), (2), and (3)
(2) Exposed in dropped or suspended ceilings in other than one- and two-family and multifamily dwellings
(3) As service-entrance cable
(4) In commercial garages having hazardous (classified) locations as defined in 511.3
(5) In theaters and similar locations, except where permitted in 518.4(B)
(6) In motion picture studios
(7) In storage battery rooms
(8) In hoistways or on elevators or escalators
(9) Embedded in poured cement, concrete, or aggregate
(10) In hazardous (classified) locations, except where permitted by the following:
a. 501.10(B)(3)
b. 502.10(B)(3)
c. 504.20
(B) Types NM and NMS. Types NM and NMS cables shall not be used under the following conditions or in the following locations:
(1) Where exposed to corrosive fumes or vapors
(2) Where embedded in masonry, concrete, adobe, fill, or plaster
(3) In a shallow chase in masonry, concrete, or adobe and covered with plaster, adobe, or similar finish
(4) Where exposed or subject to excessive moisture or dampness

I don?t see any thing that prohibits the installation of nonmetallic cable in either of these raceways.

 

[vanwalker]

Re: NM in Raceway

In 2005 NEC if not prohibited then it must be OK. THANKS GEO

 

[augie47]

Re: NM in Raceway

If enforced, please watch for Note 9 to thbe tables (Chapter 9)

(9) A multiconductor cable of two or more conductors shall be treated as a single conductor for calculating percentage conduit fill area. For cables that have elliptical cross sections, the cross-sectional area calculation shall be based on using the major diameter of the ellipse as a circle diameter.

 

[Towzzer]

Re: NM in Raceway

I was thinking more along the lines of 100 feet of UF inside sch40 PVC underground.

 

[roger]

Re: NM in Raceway

Originally posted by Towzzer:
I was thinking more along the lines of 100 feet of UF inside sch40 PVC underground.

No problem, see 352.22, then notice that 340.12 doesn't prohibit this UF from being installed in this PVC.

Roger

 

[al hildenbrand]

Re: NM in Raceway

Nothing wrong with a little extra physical protection.

If I put that UF in Rigid Metallic Conduit, I could even raise it to 6" and dispense with GFI protection on the feed end.

 

[peter d]

Re: NM in Raceway

Originally posted by Towzzer:
I was thinking more along the lines of 100 feet of UF inside sch40 PVC underground.

If you allready have a complete raceway system, I would simply install THWN conductors, simply because they would be easier to pull. And as you start getting into the larger sizes of UF, the flat construction starts to really interfere with round pipe.