|
1 members (Scott35),
136
guests, and
11
robots. |
|
Key:
Admin,
Global Mod,
Mod
|
|
|
|
Joined: May 2003
Posts: 2,876
OP
Member
|
Alright, I'm posting this to stir everybody up! (Kidding ![[Linked Image]](https://www.electrical-contractor.net/ubb/biggrin.gif) ) And, I'm not trying to put anyone down, or criticize the many varied methods that are allowed in various places. (Although, it is not allowed in many places, some places it is.) But would you: Use romex in a church? Use romex in a grocery store? Use romex in a 40 story office bulding? Use romex for a 277/480v circuit? My answer is No, to all of the above. Even if you could, would you?
Mark Heller
"Well - I oughta....." -Jackie Gleason
|
|
|
|
|
Joined: Feb 2002
Posts: 840
Member
|
Yes, why not? I don't see the problem.
I have seen NM cable used in 3 of the 4 applications you mentioned (except the 40 story building) without any problems.
I've never understood the resistance to using NM.
It is a safe, code compliant wiring method and is very cost effective.
I don't buy the "smoke toxicity" argument often cited as a reason for disallowing NM cable in commercial spaces. What about the other toxic smoke that is contributed when carpet, computers, office furniture, paint, and other chemical compounds burn?
Peter
Peter
|
|
|
|
|
Joined: Jan 2003
Posts: 4,391
Moderator
|
I think it looks out of place in many of the locations you list. But without some facts to show it is unsafe what is the problem. I have some experience with the grocery store question and when there is a reason we have to run MC in place of NM the office tells us it is about a $60,000 change. (80,000 to 100,000 sq ft stores) So if you try to bid the job MC when everyone else is bidding NM there is not much chance you will get the job. We service about 100 large grocery stores and most are NM, very few service calls have to do with the NM. Most calls are failures of THWN in under slab raceways or problems with breakers and relays. Hey stir things up. Bob
Bob Badger
Construction & Maintenance Electrician
Massachusetts
|
|
|
|
|
Joined: Jun 2004
Posts: 613
Member
|
334.12(A)(1)of the 2002 NEC does't allow romex as open runs above drop ceilings in other than one & two family and multifamily dwellings.
Article 518 does't allow romex in portions of that building that are designed for assembly of more than 100 persons.This section could apply all of the areas you mentioned.
shortcircuit
|
|
|
|
|
Joined: Jan 2003
Posts: 4,391
Moderator
|
518 has no influence on a grocery store or a 40 story building as a whole. 518 will keep NM out of the church assembly area it does not keep it out of the ancillary areas like bathrooms, offices, hallways, etc. Yes 334.12(A)(1) has changed the rules for most, but being a MA resident that was amended so it is not a consideration for me. ![[Linked Image]](https://www.electrical-contractor.net/ubb/smile.gif) Use romex for a 277/480v circuit? NM is rated 600 volt for a reason and yes we use it. I will admit I am not comfortable pushing a 12/3 out of the way with 480 volt, 3 phase live in it. Bob
Bob Badger
Construction & Maintenance Electrician
Massachusetts
|
|
|
|
|
Joined: Feb 2002
Posts: 840
Member
|
Bob, But without some facts to show it is unsafe what is the problem. I agree. I wanted to bring this one up because MA did cite a very safe history of NM use, hence the suspended ceiling ammendment in the MEC. I'm pretty sure I read that in the ROPs, but I can't quite remember. Correct me if I am wrong, but didn't the MEC also allow NM to be used in buildings of any height long before the '02 NEC made the change? Since I am not from MA I am going by hearsay and may be totally screwing this one up. ![[Linked Image]](https://www.electrical-contractor.net/ubb/wink.gif) I will admit I am not comfortable pushing a 12/3 out of the way with 480 volt, 3 phase live in it. I don't think anyone would be. Nobody should feel comfortable pushing any live cable around, MC, AC or otherwise. Peter
Peter
|
|
|
|
|
Joined: May 2003
Posts: 2,876
OP
Member
|
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.
Mark Heller
"Well - I oughta....." -Jackie Gleason
|
|
|
|
|
Joined: Feb 2002
Posts: 840
Member
|
e57, 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. Huh? That is a ridiculous statement to make. Do you have any facts to back this up? How on earth does the wiring method factor into that?? Until hard facts prove otherwise, I maintain that NM is a safe, code compliant and cost effective way to do the job. I'm sure I am biased because the use of NM has widespread acceptance where I live. But I still don't understand where this dislike, almost hatred, of NM comes from at all. ![[Linked Image]](https://www.electrical-contractor.net/ubb/confused.gif) Peter
Peter
|
|
|
|
|
Joined: Jul 2002
Posts: 717
Member
|
Ok here we go.. If it is a multi use commercial situation such as a strip mall, and you use romex to wire lets say a furniture store or shoe store, but nearby they put in a greasy spoon fast food counter, you could get some serious rat chew the romex up problems over time. I have seen just such a situation before firsthand. The application was a single story strip mall made with timber and had drop ceilings. the rats were able to get around the firewalls (mostly where trades did a lousy job of sealing). I found sections of very nicely completly stripped energized cable runing in metal studs behind sheetrock which was removed for remodel work. At least the guy who ran it used insulated bushings where he passed thru stud openings.
|
|
|
|
|
Joined: May 2003
Posts: 2,876
OP
Member
|
Ok Peter,
Yeah, the 911 referance was a bit over the top... But smoke and fire travel facts are well documented. You can try it yourself. Put a 3' length of MC and NM on a brick wall, hit them both with a MAPP gas torch at the bottom, judge for yourself.
And, it's not that I hate it. But like anything else, it has a place. Single family home under 3 stories, fine! 6 story apt. building, no. A 40 story building NO WAY!
Mark Heller
"Well - I oughta....." -Jackie Gleason
|
|
|
|
Posts: 22
Joined: August 2009
|
|
|
|
