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| Subject - places of assembly | |
| kyelec | i have a church, probally about 3000sf chapel. but it has wood frame,some inspectors are allowing nm cable. the bld would be a place of assembly butdue to it being built of wood would that place it under the exeption, where i could wire it with nm-cable? |
| AMPMWIRED | using nm-romex in other than a single family res. is a bad idea.The code states that you can use nm cable up to a three story bld.(motels, condo, etc.)The price of the mc-cable,emt or flex condit may be a little more money but the labor is almost the same.You will have no problem with city inspection if you use metalic conduits. |
| JimmyDee | The code does not distinguish the number of sq feet but how many persons are going to be there. 100 is the magic number to be considered an assembly hall and then the following article is to be used: ARTICLE 518 Places of Assembly 518.1 Scope. This article covers all buildings or portions of buildings or structures designed or intended for the assembly of 100 or more persons. 518.4 Wiring Methods. (A) General. The fixed wiring methods shall be metal raceways, flexible metal raceways, nonmetallic raceways encased in not less than 50 mm (2 in.) of concrete, Type MI, MC, or AC cable containing an insulated equipment grounding conductor sized in accordance with Table 250.122. Exception: Fixed wiring methods shall be as provided in (a) Audio signal processing, amplification, and reproduction equipment — Article 640 (b) Communications circuits — Article 800 (c) Class 2 and Class 3 remote-control and signaling circuits — Article 725 (d) Fire alarm circuits — Article 760 (B) Nonrated Construction. Nonmetallic-sheathed cable, Type AC cable, electrical nonmetallic tubing, and rigid nonmetallic conduit shall be permitted to be installed in those buildings or portions thereof that are not required to be of fire-rated construction by the applicable building code. (this is areas like the entry way, small class rooms, office, etc.) Jim |
| David Hyatt | I have never understood not being able to use romex in some buildings. It is ok to use romex, (un-safe) romex in a building you are going to be in during working hours 8:00 to 5:00 and you can use this unsafe wiring where you sleep at night.??? Does that make any sense? |
| Electricman | David, From what I understand the approved wiring methods for places of assembly have a higher safety factor than for lets say residential use. IE continuous duty verses non-continuous duty loads. But I hear what your saying as long as the methods are correct why not be allowed to use romex. There is an article in Electrical Contractor Mar 04 issue about an contractor who could save $150,000 in elec cost by using romex over conduit or mc in a high rise apartment complex in Fort Worth. The appeals board rejected the proposal 8-0. |
| Electricman | Oops forgot to answer origional question. I wired a church that was all wood frame construction. Nevertheless the AHJ insisted upon MC cable throughout. |
| Ryan_J | Electricman: If (and only if, IMO) the building was one-hour construction (Type VA or Type V-one hour), was your AHJ correct. |
| Electricmanscott | AMPMWIRED can you give us some details on why using romex in anything other than single family dewllings is a bad idea? |
| cs409 | kyelec, the best way to get the correct answer to your question is to go down and ask the AHJ what they will ok and what they will not ok.... |
| renosteinke | The funny things about codes is that they all derive from 'common practice-' often without defining that practice, or identifying the source. The (earlier) limits on the use of romex is such a case. The earlier limits of romex just happened to parallel restrictions on baloon-frame construction. Romex was assumed to be intended for relatively simple, residential work in simple homes. Get much larger than that, and most of the advantages were lost as different construction methods were used. The isue wasn't so much that romex was "unsafe," as "impractical.' Romex was also intended to allow a lesser qualified person to do the job, with a minimum of specialised tools. With the increase of our use of electricity, the rise of power quality issues, and the growing complexity of homes -not to mention remodeling, or home offices and workshops- the utility of romex is once again an issue. As for this "chapel:" this seems to be a small one. I have often seen such small structure projects try to work both sides of the code (the land is zoned 'residential,' so residential methods are OK; but it's not really a house, so we don't need a kitchen or bath, or a receptacle every twelve feet....). I say it is foolish to play those sorts of games. As a "chapel," it will be used by many people, for a variety of purposes over time. It is not unreasonable to see an elaborate sound/light system for the choir, periodic bake sales/bingo nights, etc., in the building's future. Even the HVAC system may have more involved controls than is usual in a home. These things have to be taken into account by the design. Maintenance, and the ease of remodeling, assume greater importance. It is important that your customer understand the limits of romex. Even under current rules, the use of romex is limited to fire-resistant designs. I believe that the use of romex is neither wise nor allowed in this chapel. I believe that the zoning classification has NO relation to the type of wiring practices to be followed. |
| Pierre Belarge | One of the basic reasons NM cable is not permitted in places of public assembly is the smoke that is emitted when the sheathing is burning. This smoke is highly toxic and spreads quickly. The reason for permitting NM in dwellings is that there are generally less people in dwellings, and evacuation takes less time. The NEC states places of public assembly as 100 persons, be careful as some states have their own code - such as NY State mandates places of public assembly to 50 persons. This is also based on density of the persons as well. Pierre |
| Russell120 | Pierre's answer is right on the mark as to the reasoning of the code. One confusion with "places of assembly" and with "construction types" is that the building codes (IBC in North Carolina)use a different nomenclature from the NFPA. It causes a lot of confusion. I know with the IBC that the smallest grade of "assembly" starts with an occupant load of 50 people. The best bet is to ask your AHJ building inspector (not necessarily the electrical inspector unless he does both) what they consider a place of assembly. When you start getting into building codes and their interaction with the NEC is gets very tricky (and annoying). |
| JimmyDee | quote: If you think about the rationale behind this concept, it will show you how rational it is. They will allow PVC conduit, which has more plastic than the NM sheathing, plastic carpet, plastic in the paint, plastic covering on the chairs, plastic in the plumbing, plastic in the drapes, plastic light fixtures and who knows where else. I would think a church with 150 people could be cleared out in less time than 6 sleeping people in a house. Maybe my thinking is wrong but then again maybe they are allowing for sleeping people because of a boring sermon.  Jim |
| Russell120 | A house does not have three-hundred people trying to pile out of the same exit chocking on poisonous fumes. Assembly fires have often had some of the highest "body counts" of any type of fire. Furthermore, many people do die in house fires, so I am not sure it is such a great analogy. PVC can only be used in an assembly if it is encased in 2" of concrete. The parts of the building (back offices, etc.) that are not a part of the assembly area and its exits do not have to follow the assembly requirements. That the code is not always consistent is certainly true (it is done by different committees), but why is there this rush to the cheapest easiest type of construction? Plastic, even some of the types that burn slowly and are thus plenum rated, is generally a very bad thing in a fire. |
| JimmyDee | Keep in mind, I'm not saying that romex should be used in an assembly hall, I'm saying that the plastic and fumes is a poor reason to not use romex. We have many other sources of fumes that will produce far more toxins than the romex will. Most of the romex when used, will produce fumes that are inside a wall and far less likely to get into the breathing air in case of a fire than other plastics that are in the room. I just don't think the fumes produced by romex is a valid reason for not using romex in an assembly hall. I think you would have a greater reason not to use it in a house for that reason. Jim |
| JimmyDee | The original question was about a church and I think this NEC article may shed some lite on the question. It looks like plastic and PVC are both approved for some types of assembly halls like a church. 518.4 Wiring Methods. quote: |
| Russell120 | Your right that they can use it behind walls. I did not catch that code change from 1999-2002. A 15 minute rating is basically 5/8 sheetrock on wood (Maybe even 1/4" sheet rock). I think it was after the 1999 Code that I read a commentary to the effect that you might as wall not have a "Places of Assembly" section because they have watered it down so much. However, since I don't think they should PVC (even though you obviously can) then I'm certainly not going to like the use of romex. But I agree that the whole section is a bit out of wack. Why don't they just let them run knob and tube while they are at it? |
| JimmyDee | quote: Actually, the old knob and tube wiring was some fairly safe installation. Wires were always over a foot apart. All it really needed was the ground wire. We called the system, a #14 buss way. It was a good installation for the amount of electrical devices it had to service. Jim |
| Pierre Belarge | Jimmy The NEC does not have control over other than electrical - lets not give them any ideas.  BTW - Happy Holidays!!!! Pierre |