Alright here we go.... There reason I brought this up is I had an arguement with a PM about it a while back. And everytime I see NM in a situation that I "feel uncomfortable" with it, I don't think anyone else should be either. Hense, I won't put it in! If I, not a layman, am not comfortable with it as a proffessional, why should I expect to the layman to be. It's a little too much philosophy isn't it?
So, this PM (when the code changes were coming) out said, "Yeah, you can now use NM anywhere! You can use romex in a church, a grocery store, a 40 story office bulding?"
I said, "Well when it comes down to it, NO I WON'T!" Then sited the quote at the bottom of the post.
The Code is a minimum standard, right? Wouldn't want you doctor to do the bare minimum, right?
We don't use it in Theaters, and places of assembely do to toxic possiblities in a fire, and rapid fire spread. What makes a church any different than the use of a theater? A grocery store may as well be a place of assembly, on average 100 to 300 people could be "assembed" in one building at any given time. Imagine Sept 11, if those buildings were done in NM? Quite a few people assembled there. Extreme example, but still fewer people would have made it out if it had been wired in NM.
Bob, you said, "I will admit I am not comfortable pushing a 12/3 out of the way with 480 volt, 3 phase live in it." Neither am I! One reason I won't install it, for that voltage, rated for it or not. But that's me. I don't think it provides the physical protection of MC, or AC.
Like I said, in the original post. I'm not trying to put anyone down, or criticize... I am just sick of people expecting the bare minimum from me! If I miss a bid because I went MC, against a guy doing it with NM, my wallets empty, but my conscience is clean.
Fortunatley, I don't have deal with it
yet, as SF doesn't allow NM in commercial buildings due the higher
fire rating imposed on them, than on residential. So when I do have to worry about it, someone is going to have to show me the
Fire Rating of the building before I decide to use NM, or not.
Commentary from 334.10 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.
