Romex in commercial buildings? - ECN Electrical Forums

Alright, I'm posting this to stir everybody up! (Kidding [Linked Image]

) 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?

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

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. [Linked Image]

Bob

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

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]

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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,

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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]

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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. [Linked Image]

Nobody should feel comfortable pushing any live cable around, MC, AC or otherwise.

Peter

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.

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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.

e57,

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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]

Peter

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.

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!

macmikeman,
Yep, never seen rat damage on MC or pipe. I have found a dead rat locked on to 12/2 romex.

"E"

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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.

The grocery stores we wire certainly have more than 100 people in them quite often, that does not make them a place of assembly.

Look carefully at the examples of places of assembly in 518.2(A), they are not simply buildings that hold more than 100 people. They are places where more than 100 people are expected to be densely packed.

The added smoke danger presented by NM to the building occupants is only the additional smoke generated from the jacket. We can not count the insulation on the conductors as this is present in MC/BX/EMT etc. Even though these conductors are in metal raceways they will generate smoke that will leak out of boxes and fittings.

But here is what gets nuts in my opinion, the wiring methods in a typical building only form a very small percentage of the smoke producing products in the building.
Also the wiring methods are spread out mostly in walls and ceilings.

What about the rug that is everywhere, the furniture, the typical plastic stuff that is through out the building? These items are actually 'in' the same spaces that the people are.

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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!

Well seeing as you said you have a PM it is not up to you. [Linked Image]

You want to make decisions like this you will need to run your own company. [Linked Image]

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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?

Nothing makes a theater different from a church, both may have portions that may be NM and both may have portions that must not be NM.

Bob

I think I would require pipe/flex in any occupancy that could reasonably expect major revisions or renovation within 5 years, and I wouldn't expect different as an EC.

Look at the average lifespan of a strip mall occupancy... IMHO, the use of NM in such an occupancy would lead to all sorts of rat's nests from abandoned wires from the prior occupant when the (non-english-speaking low bid psuedo-)EC working for the landlord/management company does a rush job for the new tenant.

E57,

I don't deny for a second that NM cable is more flammable, you are absolutely correct. And yes the rats chewing on the insulation is another issue to consider, but it doesnt weigh heavily on my mind, as rat infestation speaks of other serious problems.

Consider this. A few years ago there was a devastating fire at The Station nightclub in West Warwick, RI (my home state.) The entire building was consumed by flames in less than 3 minutes, and 100 people died as a result. Numerous others were severely burned and disfigured by the blaze.

The nightclub could have been wired entirely in RMC and it would have made no difference in the spread of the fire. The main contributing factor was highly flammable packing foam that had been put on the walls for sound deadening. This, of course, was a serious code violation but not an electrical one.

So the point is, as myself and Bob have both mentioned, once you fill an occupancy with toxic-laden combustibles, the wiring method quickly becomes irrelevant in my opinion.

Peter

edited to add: The Station fire ushered in a total overhaul and complete revision of Rhode Island's fire code. It is now one of the strictest fire codes in the nation.

[This message has been edited by CTwireman (edited 09-15-2004).]

Doug I mean no ill will at all, but I want to ask what your experience with NM is?

I believe you are in an area that pretty much denies the existence of the product. [Linked Image]

I have grown up with NM and our buildings are not predominantly rats nests. NM just like pipe can be installed, modified, maintained in a neat and workmanlike way or it can be all hacked up. IMO it is the tradesman not the product that has the biggest influence on the job.

JMO. Bob

Bob,

No offense taken, or meant.

What I was suggesting is that, when an occupancy is vacated, and then customized for another renter with a different type of business that requires less outlets and KVA (say former pizza joint turned boutique, or hair salon turned record store), the temptation will be there for a fly-by-nighter to simply "abandon in place" and re-wire for the demands of the new occupancy. With NM this can be much uglier than a raceway system.

I wasn't saying that NM by itself in all installations is a rat's nest. Trust me, I've seen enough crooked EMT and kinked MC to know that what you say about quality being the tradesman not the product is gospel.

BTW, although the lake shore communities of Lake County do tend to ignore the rather plebian NM cable family [Linked Image]

, I rewired an old K&T house in Kenosha, WI using NM along the old wire runs. I've also used it in Milwaukee at my ex (thank God!) GF's folk's place, and in my Mom's in Decatur, and my wife's folks in St. Louis, Mo. Not a lot, compared to many of you guys who run it on a daily basis, but enough where I do recognize it's versatility and usefulness.

[dig] I still love my pipe, though! [Linked Image]

[/dig]

I had no idea that anyone was concerned about the smoke toxicity of NM...very interesting. I'd always assumed that it wasn't allowed because it's such a wimp in the class of physical protection of the conductors. In this area it's allowed in the county, but not allowed in the city jurisdictions.

I run so little of it that I don't keep it in the truck. Part of it may be that it seems like cheap materials for low-bid work. It's not the type of business that I go after. When I run NM I feel like a weekend warrior, when I run EMT I feel like an electrician.

Dave

Doug

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Bob,
No offense taken

Cool

Dave I am no weekend warrior. [Linked Image]

What do you guys do to the NM that it is so likely to be damaged? [Linked Image]

Weekend warrior? [Linked Image]

Here,there are FEW commercial buildings,and the most of them are wood-frame.

We do mostly residential,because that's what there is to do. We'll do a small commercial job sometimes,mostly small office spaces. I'd like to pipe all of it,but there's no way.

The homes we do are mostly in the 4-8000 sq.ft range.

We've done a couple small resturants in the last couple years,and ran Pipe and MC cable.

With no permits or inspections for the majority of it, We have to bid against the $12 and hour guys. Most of them wouldn't know a stick of emt if it bit them,but they get a lot of the work.

An NM-B job can be done neatly and safely as anything else imho,and it has a good track record here. It's good if you can pick and choose work and do all commercial,but we don't have that option unless we move someplace else.

Russell

Chill guys, I said I feel like a weekend warrior when I run NM, I'm not saying anything about anybody else.

Of course it's easy enough to run NM without damaging it, but having my circuits surrounded by steel makes me feel all warm & fuzzy inside, as well as those larger bank deposits.

I ran 4 circuits across a house this week in one conduit, and I'm not sure there would have been any great savings in running (4) NMs.

Dave

When I posted the topic I knew there were going to be some opinions. And, I got them Thanks! I still have my own.

Peter, I was going to bring up the nightclub fires, and the casino fires. And glad you mentioned,

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... ushered in a total overhaul and complete revision of Rhode Island's fire code. It is now one of the strictest fire codes in the nation.

The same thing happens everytime there is a big death count fire. They go through and start getting rid of combustables, and toxics. But one of the things most places do, is question the use of NM after an event like that. The Contractors and Developers complain, and then go back to using it.

It comes down to reducing fuel load in the building, I know there are some Fire Fighters on the forums that would understand that. And it should also be noted that most deaths in fire are smoke inhalation related. Many building code require reductions in combustables, and low smoke materials. Plenum, and riser rated comm wire for instance. Tin can framing, etc. Most office furnature has to have a higher fire retardant rating than most household items. This is all done for a reason. The NFPA writes our code, and I think this is one thing they caved in to some lobbyist for. Just my opinion.

Bob, the PM seems excited about it, but the Boss/Owner is on my side on this. And, I have been out on my own, and will again, when the time is right. And hopefully, I'll never have to worry about it as SF may write it own code as it does for many things. And, NM isn't legal here now in commercial, or multi-unit resi. But I won't feel good about it ever changing.

FYI, any wiring added to my own house is MC, or piped.

Anyway, thanks for all the comments....

This is one of the reasons it is a great country we can, for the most part do things are own way. [Linked Image]

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having my circuits surrounded by steel makes me feel all warm & fuzzy inside, as well as those larger bank deposits.

So you would walk away from the one, two or three approximately $500,000 to $700,000 commercial NM jobs we do.

Cool, more for us. [Linked Image]

The majority of the work we do is MC and EMT, but I see no reason not to use NM in a code compliant manner.

My experience with NM in commercial is mostly super markets, the fuel load presented by NM pales in comparison to the fuel load presented by the products down on the sales floor where the people are. [Linked Image]

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FYI, any wiring added to my own house is MC, or piped.

FWIW Any wiring added in my house is NM and my new service is SE. I did bend up a piece of RMC for the service but it did not hide as well as SE. [Linked Image]

To each their own. [Linked Image]

Bob

[This message has been edited by iwire (edited 09-16-2004).]

Count me as another EC from IL that hates NM. When I see NM it is almost allways installed by a non electrician. I see some homes south of here that are built with NM. Then I find out I can't just pull another switch leg or another circuit. I don't work in Chicago but I've been told that some cases the electrical boxes need to be sealed or plenum in a building.

Tom

I have to admit I am still confused and can not get a straight answer on the new code language requiring NM cable in non-dwellings to be within a 15 min rated concealment. This appears to prohibit it if you have wood wall covering or wood exterior. Any thoughts?

necbuff, I with you on that... Essentially we need to look in Annex E after determining what the Fire Rating of the building is supposed to be! And even then, it only allowed in certain areas, with a certain finish. This is the commentary in Annex E...

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This annex is new in the 2002 Code. This table is extracted from NFPA 220, Standard on Types of Building Construction. It explains the various construction types and has been provided for use in conjunction with 334.10.
This annex is not a part of the requirements of this NFPA document (the 2002 NEC) but is included for informational purposes only.

(Parrenthesis added by me)
So what I was saying earlier in the thread is, (although not in those exact words) I guess we all have to get NFPA 220, Standard on Types of Building Constructionin order to figure out where we can, and can not use romex.
---------------------------
I pitty the guy who wires a building in NM, and then finds out it was supposed to be a type I, or type II fire rating!

[This message has been edited by e57 (edited 09-17-2004).]

What you need is the blessing of the building official. I could use romex in a 200,000 sqaure foot building if I meet some are exceptions in the building code.

Determining allowable height and area of a building, and therefore type of construction is a difficult thing.

The NFPA 220 won't do anything, because it isn't adopted as a building code. Even if it were, you need a lot of info before you can determine T.O.C.

Hola Ryan, I was wondering when you would show up on this one.... Seems up your ally. You must have posted while I was editing my last post... So who exactly would the last word be with on that? Building spec's, or Local AHJ, or the Insurance Company?

As far as which wiring method is better, is a moot question. For it is not the method that is so important as the skill (and pride) of the installer.
I have seen all different kinds of wiring methods that show great skill and pride, and I have also seen disasters including all different wiring methods.
Both wiring methods have their place, and both are very safe if installed properly.

As far as building types, in most states the type of building construction is supposed to be labeled on the print. If there are no prints, or they are not labeled, then the building department has that jurisdiction.

Pierre

Well I might as well come clean, I live in a state that has a lot of faith in plain old NM and you know what? Our buildings are not burning down at an alarming rate and I have gone on very few service calls that NM was the cause of.

Here is one of our State amendments.

Mass. Electric Code.

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334.10(3). Add an exception as follows:

Exception: Type NM, Type NMC, and Type NMS cables shall be permitted to be used in one and two-family dwellings, multi-family dwellings and other structures of Type I and II construction, provided that where such dwellings or structures exceed three floors above grade Type NM, NMC and Type NMS cables shall not be permitted to leave the floor or dwelling unit from which the cables originated.

So yes I am bias but I am also into facts and figures, not feelings.

If someone can point to some facts that the buildings in this state are more dangerous to the occupants in a Raceway building please point me to them.

[Linked Image]

Bob

Couldn't find you facts and figures, but a little history on the topic. We are not alone in our opinions! [Linked Image]

Found this article: http://www.rexelusa.com/power_outlet/PO_V2_N2/146_Controversy.pdf

A history of the overturning of the "3 floor rule" http://www.nfpa.org/PDF/Minutes0701.pdf?scr=nfpa- (Starting on page 12)

Mass' (the state I grew up in, by the way) has thier code, San Fran' still has it's own. [Linked Image]

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('99 NEC)336-5(a). Uses not permitted. Add a new section as follows:
(10)In any nonresidential structure or occupancy.

Thanks, interesting reading, well sort of. [Linked Image]

In all that I did not see any reason not to use NM in commercial occupancies. [Linked Image]