ECN Forum

NM Cable

Posted By: George Little

NM Cable - 05/23/05 09:46 PM

Can you use NM cable as the wiring method for a Type I construction, high rise building? per NEC 2002 Edition?
Posted By: Ryan_J

Re: NM Cable - 05/23/05 10:36 PM

No.
Posted By: e57

Re: NM Cable - 05/23/05 10:57 PM

Depends on other building codes, where it is, and the finish of the cavity it is in. See Annex E. The shaded stuff is permitted, I think, depending on what you call "Combustable"?

(And who's string in the building department gets pulled! And what type they want to call the building, or parts of it. Something I see a lot of where I'm at lately. First floor commercial type I, mixed type III, IV, and V for a few floors, type II, and I again. SF hasn't hit 2002 yet, and we don't know how they will modify it, but it makes you wonder in situations like those, how do you bid?)

Other than that confusing ball of wax, it is a combustable material in my mind, and say no! I have argued this one before with someone else, and personally I think the NEC muddied the waters on this, instead of making it in any way clear one way or the other in the way this was written. It's not spelled out in the "Permitted", or in the "Not Permitted".

The NEC commentary does not clear it up either:
Quote
A well-established means of codifying fire protection and fire safety requirements is to classify buildings by types of construction, based on materials used for the structural elements and the degree of fire resistance afforded by each element. The five fundamental construction types used by the model building codes are Type I (fire resistive), Type II (noncombustible), Type III (combination of combustible and noncombustible), Type IV (heavy timber), and Type V (wood frame). Types I and II basically require all structural elements to be noncombustible, whereas Types III, IV, and V allow some or all of the structural elements to be combustible (wood).
The selection of building construction types is regulated by the building code, based on the occupancy, height, and area of the building. The local code official or the architect for a building project can be consulted to determine the minimum allowable (permitted) construction type for the building under consideration. When a building of a selected height (in feet or stories above grade) and area is permitted to be built of combustible construction (i.e., Types III, IV, or V), the installation of nonmetallic sheathed cable is permitted. The common areas (corridors) and incidental and subordinate uses (laundry rooms, lounge rooms, etc.) that serve a multifamily dwelling occupancy are also considered part of the multifamily occupancy, thereby allowing the use of nonmetallic sheathed cable in those areas.
If a building is to be of noncombustible construction (i.e., Type I or II) by the owner's choice, even though the building code would permit combustible construction, the building is allowed to be wired with nonmetallic sheathed cable. In such an instance, nonmetallic sheathed cable may be installed in the noncombustible building because the Code would have permitted the building to be of combustible construction.
Annex E provides charts and other explanatory information to assist the user in understanding and categorizing the exact types of construction under consideration. A table to cross reference building types to the various building code types of construction is provided in Annex E also.
Posted By: e57

Re: NM Cable - 05/23/05 11:00 PM

Ryan, what if it is a high rise apartment, as a "multi-family dwelling"? The code doesn't seem to exclude it.

(if portions are type 3, 4 and 5)

[This message has been edited by e57 (edited 05-23-2005).]
Posted By: harold endean

Re: NM Cable - 05/24/05 01:03 AM

George,

I think in NJ you still can. I don't believe that NJ adopted that section of the NEC which would allow the NM wire above ceilings.
Posted By: George Little

Re: NM Cable - 05/26/05 12:19 AM

The 2002 NEC tells us at 334.10 (1)(2)(3) in which types of construction that NM cable is permitted (Types III, IV, & V). 334.12 does not exclude NM cables in Construction Types I and II. That being true, NM cable is suitable in Construction Types I and II under the 2002 NEC. The 2005 NEC on the other hand at 334.12(A)(1) clarified that NM cable is not permitted in "any dwelling or structure not specifically permitted in 334.10 (1),(2) and (3)."

The State of Michigan has for as long as I can remember allowed NM cable in Construction Types I & II with no 3 floor limitation. This was done via amendment and we have an excellent track record.

[This message has been edited by George Little (edited 05-25-2005).]
Posted By: Ryan_J

Re: NM Cable - 05/26/05 12:44 AM

In dwellings, the type of construction doesn't matter, and you can put it in dropped ceilings. [334.10(1) and 334.12(1)].

In multi-family dwellings, you can use it in type 3, 4 or 5, and you can put it in dropped ceilings. [334.12(2) and 334.12(2).

In commercial, you can use it in type 3, 4 or 5 construction, but you can't put it in a dropped ceiling. [334.10(3) and 334.12(2)].

E57: You can't change type of construction in the middle of a building. TOC governs the entire structure. See chapter 6 of the IBC.
Posted By: macmikeman

Re: NM Cable - 05/29/05 04:29 AM

Question for Ryan J. Ryan, what does the IBC stand for ? Is it International building code ? Honolulu City and County works off the Uniform Building Code. I do not know how similar they are to each other, but I still am uneasy running romex in any structure over 3 floors yet, because of possible confusion on my part or the local ahj about the different types of construction may cause my having to rip the stuff out and lose time and money.
Posted By: e57

Re: NM Cable - 05/29/05 08:31 AM

Ryan, I'm not sure if it is happen where you are. But I have been seeing more and more "multi-use buildings" with "envelopes" of fire and building types.

Garages and Commercial in one type, then wood framing above that for residential, and mechanical and public access spaces in another type on the roof.
Posted By: Ryan_J

Re: NM Cable - 05/29/05 03:57 PM

Yes, the IBC stands for Internaional Building Code. It is very similiar to the UBC, especially in this area.

e: I understand what you are saying, but please believe me...type of construction governs the entire structure, not just portions of it.

The way TOC works is it mandates the size and height of the building, based on occupancy type. For example, take a skyscraper. These must be built to the most restrictive TOC there is, which is 1A. That is because egressing out of a 100 story building is a difficult thing...that means nothing that can burn can be in the building. The fact floors 1-48 are business, then floor 49 is residential, then floors 50-100 are business again doesn't change the fact that I have a scyscraper.
Posted By: e57

Re: NM Cable - 05/29/05 05:50 PM

Ryan, this is an example of the type of manipulation of TOC I'm reffering to:
Quote
SECTION 601 CLASSIFICATION OF ALL BUILDINGS BY TYPES OF CONSTRUCTION AND GENERAL REQUIREMENTS

Section 601.2. Add the following sections:

601.2.1 Combination Type I garage and multiple buildings or structures. The construction of more than one building or structure on top of a common Type I garage shall be permitted, provided the following conditions are met:

601.2.1.1 Each building or structure on top of the garage shall have direct frontage onto a street or to an approved permanently open driveway equivalent to a street. The driveway shall be not less than the required street width for the occupancy and type of building or structure served. To establish the garage roof as an equivalent street level, the garage roof and access to the roof shall be designed to support the weight of mobile fire apparatus. Access and maneuvering area for that apparatus shall be as required by the Fire Department.

601.2.1.2 Where the building or structure means of egress proceed to the street level, the measurement of stories for purposes of determining standpipe and egress requirements shall be from such street level. Where the building or structure means of egress terminates on the top of the garage as the equivalent ground level, the measurement of stories for purposes of determining standpipe and egress requirements may be taken from the top of the garage. Approved fire hydrants shall be provided on top of the garage at not more than 200 feet (60.96 m) spacings in locations approved by the Fire Department.


"Live-work" lofts being a perfect example, with type 1, and 2 cores, and egress. An example of this being a type 1 garage, with a theater on top, and wood framed mixed use residential wrapped around it. 6-story building as I see it, but considered 2 or 3 seperate structures the the way the planning dept. sees it. And, over the last few years, I have seen further manipulations of TOC within 12-15 story apt. buildings, build outside of type 1/2, and expect more in the future.

Anyway, my point was, it that the way the NM section was re-written for 2002, made it more vague, rather than clear from the electricians standpoint IMO. "3 stories" was easy!



[This message has been edited by e57 (edited 05-29-2005).]
Posted By: Ryan_J

Re: NM Cable - 05/29/05 11:04 PM

I would have to say that that is one of the dumbest things I have ever seen.

I think when people don't agree with a particular code section, they should change it on the national level, not just amend the hell out of it so that no two states have similiar requirements.

The whole reason the ICC was formed was so a designer living in New York could design a building in LA and not have to worry about knowing some stupid local rule like this one.

Of course, California is also the only state dumb enough to adopt the NFPA 5000, so what do you do?
Posted By: e57

Re: NM Cable - 05/30/05 01:21 AM

It's a fast moving trend, it won't be long until it hit a building near you Ryan.

I have been seeing more and more of this type of building type manipulation lately.

Floor 9 of 25 in an apt building with wood framing materials allowed because it was in "Type 1 containment". Currently, I can't use romex in that building, but after October.... Who knows?

Another place built in 1915 as 12 stories is type 3. I won't put romex in it, but someone else will.

Like I said... "3 stories" was clear and easy.

Oh, NFPA 5000 was reversed: http://www.nfpa.org/itemDetail.asp?categoryID=965&itemID=23641&URL=Codes%20and%20Standards/Comprehensive%20Consensus%20CodesĀ®%20(C3)/A%20decision%20in%20California
© 2019 ECN Electrical Forums