Romex above accoustic ceiling in commercial

[wwebb]

I had a question today: If an accoustic ceiling is being attached to the truss system with no drywall layer at the bottom cord, can romex be used for lighting circuits, etc. in this area?
My reply was that the code did not list any exceptions to Art. 334.12(A)(1). However, it is my take on this that if the conditions are as he said, romex could be allowed above the bottom cord of the truss system. Any input on this would be appreciated.

 

[hbiss]

Re: Romex above accoustic ceiling in commercial

No, it's in the ceiling. What don't you understand?

That's where you would normally install your runs since you can't support them (what ever you use) from the hangers or grid anyway so how is this anything different?

-Hal

 

[wwebb]

Re: Romex above accoustic ceiling in commercial

Obviously I did not make myself clear....The code does not allow "open runs IN dropped or suspended CEILINGS". This is an unusual case as the normal requirement for fire separation is for drywall to be attached to the bottom of the bottom cords of the trusses. Since there is no "ceiling" to drop down or suspend from, this could be defined as an attic area (by some).
As the IBC defines "attic" as "The space between the ceiling BEAMS of the top story and the roof rafters", this argument would have some merit.
Please, let's hear some more argument on this!

 

[nvcape]

Re: Romex above accoustic ceiling in commercial

If the accostic ceiling is accessable, then it is still an "open" installation and NMC can't be used. Also, the ceiling must provide a 15 minute thermal barrier and might not be identified for this.

 

[iwire]

Re: Romex above accoustic ceiling in commercial

Originally posted by wwebb:
As the IBC defines "attic" as "The space between the ceiling BEAMS of the top story and the roof rafters",

So in your case the attic would be between the top side of the truss and the roof rafters.

In that space maybe you could talk the AHJ into letting NM be used.

But how will you get there without cutting through the ceiling space below?

Using your definition the space from the top of the truss down to the suspended ceiling will all be ceiling space.

Run BX or MC what is the big deal?

 

[ryan_618]

Re: Romex above accoustic ceiling in commercial

The definition of an attic doesn't enter into it. NM cable cannot be used here.

 

[wwebb]

Re: Romex above accoustic ceiling in commercial

Thank you ALL for your comments on this. The answer that I gave to the contractor was "NO", as I stated in my original inquiry. I learned a long time ago (as a contractor) to try to use the codes to my advantage, so I would research ways to technically save money. Now, as an inspector, I agree with using the codes to your advantage when it is possible, but I also must interpret WHERE, and IF the advantage may be used.
The argument about the attic space was brought up by the contractor, and I aplaud the effort and research, but as you have all agreed, this would be an illegal installation.
Thank you again.

 

[sdbob]

Re: Romex above accoustic ceiling in commercial

a couple of comments...

#1. Our area here in CA still uses the '99 code, where it is accepted.

#2. The 2002 code prohibits "open runs" in drop ceilings, it doesn't prohibit NM in "open ceilings". The 2002 handbook offers the interpretation that it's allowed as long as it has "additional protection", and offers 334.15(B) as an example of such.

 

[volt101]

Re: Romex above accoustic ceiling in commercial

If this is not in a residential application then,
334.10 Uses Permitted.
Type NM, Type NMC, and Type NMS cables shall be permitted to be used in the following:

(3) Other structures permitted to be of Types III, IV, and V construction except as prohibited in 334.12. Cables shall be concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies.

Concealed. Rendered inaccessible by the structure or finish of the building. Wires in concealed raceways are considered concealed, even though they may become accessible by withdrawing them.

So if I can get to the cables after the finish is applied, without causing the finish harm, it is not concealed...It does not belong here...Above the drop in ceiling is still accessible. Heck, so isn't the attic...

 

[Billy D]

Re: Romex above accoustic ceiling in commercial

Sone one explain why you can not run NM above a suspended ceiling. What is the danger? Is this only for commercial buildings?
If you are running romex through wooded studs to your switch and then to the light that is in the suspended ceiling you would have to change over to MC or BX? Would you change over above the ceiling or below the ceiling?

 

[inspector 102]

Re: Romex above accoustic ceiling in commercial

As I have understood the concern, it again goes back to the fire service and the entanglement of NM cable when a ceiling gets pulled down to check for fire extension. As a fire fighter I can agree with the theory. As an inspector, I personally have run into numerous occasions where the electrican pulls NM then the HVAC uses the area for return air creating al kinds of violations.

 

[iwire]

Re: Romex above accoustic ceiling in commercial

Actually I have read that this change to prevent NM above suspended ceilings was a gift to the Steel Tube industry in return for the change that allows NM above 3 story's.

Mass Electrical Code

334.12(1). Revise to read as follows:
In dropped or suspended ceilings in other than one- and two-family and multifamily dwellings, unless run so as to closely follow the surface of framing members, running boards, or the equivalent, or unless connected to luminaires (lighting fixtures) in accordance with 334.30(B)(2).

So in Mass as long as you run it tight and neat you may run NM in commercial dropped ceilings.

 

[pierre]

Re: Romex above accoustic ceiling in commercial

My understanding of the change in the '02 as to this restriction was based on safety and the time it may take people in a public space to be able to evacuate during a fire. The smoke test showed dark and toxic smoke, so they decided to not permit it in public spaces where more people could be present, than in a dwelling.

 

[iwire]

Re: Romex above accoustic ceiling in commercial

If smoke is the real reason it is strange that I can still fill that same ceiling with RNC

Makes me wonder.

 

[hurk27]

Re: Romex above accoustic ceiling in commercial

It would be nice if they could make a plenum rated NM cable that would be allowed.

 

[websparky]

Re: Romex above accoustic ceiling in commercial

If smoke is the real reason it is strange that I can still fill that same ceiling with RNC

Makes me wonder.

Me too!

Bob, please help me find where it is permissable to install RNC in these spaces you are speaking of.

Thanks,

 

[iwire]

Re: Romex above accoustic ceiling in commercial

Originally posted by websparky:
Bob, please help me find where it is permissible to install RNC in these spaces you are speaking of.

Thanks,

Dave we do not need a section that says it is permissible. What section prohibits me from installing RNC above a dropped ceiling?

I am not talking about places of assembly or 'other space used for environmental air.

Bob

[ September 03, 2004, 04:41 AM: Message edited by: iwire ]

 

[volt101]

Re: Romex above accoustic ceiling in commercial

Sounds to me like it is more of a physical protection requirement, I can still use it in the building, I just have to cover it up.

 

[mtn_elec]

Re: Romex above accoustic ceiling in commercial

can you use AC Cable (BX) in a commercial building? and over the acustical?

 

[macmikeman]

Re: Romex above accoustic ceiling in commercial

Call me every name in the book if you like, but I just hate to lift out a ceiling tile and see romex up there, except if the ceiling tile is in a residence. As a matter of fact, I see too much mc up there for my liking. I prefer conduit, run square and plumb, and properly supported. Fixture whips are fine by me in mc. This is just my personal opinion.