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Joined: Mar 2005
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I used romex in the auditorium of a movie theatre, specifically for the class 2 aisle lighting circuits. Again, this is for a 12 volt circuit. (actually it is 112 different 12 volt circuits in 14 auditoriums). Under 1999 NEC article 518-4(a) exception (c) I can do this, I think. Also I think 336-5 (4) gives me some ammo as well.
Building department objected at first, but then said they'd go along with it if Engineer wrote a letter saying it was "OK". So-the engineer writes a letter, basically saying it is "OK" with him if the building department is "OK" with it. So, the building department responds that the electrical engineer has too many strings attached. They want him to re-word the letter he doesn't want to re-word it. This could be very ugly. Finish is rapidly going up over walls....
I can run speaker wire, t-stat cable, low voltage lighting control, fire alarm cable, screen-motor LV control wire. All this is allowed per 518-4 (a) under exceptions. If I had used a #12 speaker wire cable; the building department would not have even blinked. Oh, and these guys are not electrical inspectors; they are general inspectors.
any input would be 'preciated.
thanks,
John
what do you-all think?
thanks,
John
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Joined: Jan 2004
Posts: 1,507
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NM cable is not acceptable for a Class 2 circuit per 725.52.
George Little
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Joined: May 2003
Posts: 2,876
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John, you may be ready to get the big "Do over" there. I cant see where you might be able to get away from it here. The part of 336-5(4) that mentions 518 refers to 518-4(B) (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.
FPN: Fire-rated construction is the fire-resistive classification used in building codes. Ya know for other areas of the building that don't require the same fire rating. If you could some how change the fire rating of the auditorium.... Dare I say it, feel lucky they are even giving you a chance to make an arguement about it. Many of the inspectors I deal with wouldn't be so accomadating.
Mark Heller
"Well - I oughta....." -Jackie Gleason
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Joined: Jan 2003
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NM cable is not acceptable for a Class 2 circuit per 725.52. Geoge I am not seeing that, can you elaborate? Bob
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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Joined: May 2003
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Bob, I think it goes from 725.52, which refers to 725.71 725-71. Listing and Marking of Class 2, Class 3, and Type PLTC Cables
Class 2, Class 3, and Type PLTC cables installed as wiring within buildings shall be listed as being resistant to the spread of fire and other criteria in accordance with (a) through (g) and shall be marked in accordance with (h). Another killer for the romex install is 411 which goes back to chapter 3, and back in the circle again. [This message has been edited by e57 (edited 03-15-2005).]
Mark Heller
"Well - I oughta....." -Jackie Gleason
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Joined: Jan 2004
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Thanks e57, you are correct with your answer to Bob. I was reading a bunch of stuff in 725 and I grabbed only part of what I was reading and posted it ![[Linked Image]](https://www.electrical-contractor.net/ubb/wink.gif)
George Little
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Joined: Mar 2005
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I think the Building Dept. sees a way to back out of their original compromise and I hate to say it but I think they should.
518 covers places of assembly but 520 more specifically covers Audience areas and there is just no leeway for NM in any application in these areas.
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Joined: Feb 2004
Posts: 494
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Hi,
what do you use to wire a bank, school, docs office or mall out there?
regards
greg
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Joined: Jan 2003
Posts: 4,391
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George and e57 we can either use a chapter 3 wiring method for class 2 and 3 circuits or we can use class 2 or 3 cables as listed in 725-71. Check out 725.52(A) 2002 NEC 725.52 Wiring Methods and Materials on Load Side of the Class 2 or Class 3 Power Source.
Class 2 and Class 3 circuits on the load side of the power source shall be permitted to be installed using wiring methods and materials in accordance with either 725.52(A) or (B).
(A) Class 1 Wiring Methods and Materials. Installation shall be in accordance with 725.25.
Exception No. 1: The derating factors that are given in 310.15(B)(2)(a) shall not apply.
Exception No. 2: Class 2 and Class 3 circuits shall be permitted to be reclassified and installed as Class 1 circuits if the Class 2 and Class 3 markings required in 725.42 are eliminated and the entire circuit is installed using the wiring methods and materials in accordance with Part II, Class 1 circuits. Class 2 and Class 3 circuits reclassified and installed as Class 1 circuits shall not be classified as Class 2 or Class 3 circuits, regardless of the continued connection to a Class 2 or Class 3 power source. Here is 725.25 which 725.52(A) referenced. 725.25 Class 1 Circuit Wiring Methods.
Installations of Class 1 circuits shall be in accordance with Article 300 and the other appropriate articles in Chapter 3.
Exception No. 1: The provisions of 725.26 through 725.28 shall be permitted to apply in installations of Class 1 circuits.
Exception No. 2: Methods permitted or required by other articles of this Code shall apply to installations of Class 1 circuits. Class 2 and 3 circuits can be wired with any method listed in Chapter 3 NM, MC, EMT, etc. Bob [This message has been edited by iwire (edited 03-15-2005).]
Bob Badger
Construction & Maintenance Electrician
Massachusetts
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Joined: Feb 2004
Posts: 494
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Hi,
iwire- you said: "Class 2 and 3 circuits can be wired with any method listed in Chapter 3 NM, MC, EMT, etc."
are you sure about that?
i dont think so.
-regards
greg
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Posts: 61
Joined: August 2007
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