Support of MC cable above suspended cieling

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Roger have you ever seen a ceiling that did not have this documentation. I find it hard to believe that any commercial installation designed by engineers would be done without a documented ceiling. I guess someone can buy Lowes ceilings but I bet they are documented also.
 
Dennis Alwon said:
Roger have you ever seen a ceiling that did not have this documentation. I find it hard to believe that any commercial installation designed by engineers would be done without a documented ceiling. I guess someone can buy Lowes ceilings but I bet they are documented also.
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I thought the same thing...
They have all kinds of documentation on installation, grid support, grid wire installations (ASTM 636 C), construction data for each type of grid system and weight limits. Not a word on support of fixture whips, light fixtures or how to support / attach fixtures.
Armstrong refers you back to the NEC for all of it.
 
craig127 said:
300.11 closes with... 'Cables and raceways shall not be supported by ceiling grids'.
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And the Exception to 300.11(A)(2) says

Exception: The ceiling support system shall be permitted to support branch-circuit wiring and associated equipment where installed in accordance with the ceiling system manufacturer’s instructions.
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So if the grid itself is part of the support system and has the proper documentation it would be legal, in your case there isn't any documentation to support (pun intended ;)) your support method so you do not have an argument.

Roger
 
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roger said:
Dennis, that would only come into play if the ceiling manufacturer allows for the ceiling to support the wiring otherwise, 320.30 and 330.30 can only be used in the first two examples below and then the cable assemblies would have to rest on the fixture IMO


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Roger
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I dont see any documentation just an illustration;)
I have been in touch with 3 other ceiling grid manucfactures....none have documentation to support or deny my argument.
Verbaly...zip ties are fine as long as you dont bend the grid wire and the cable or whip dosent rest on the grid.
on paper...your on your own to duke it out with the AHJ. Next time we'll strap to the stucture and be dont with it......
 
I'm not quite sure why this is even coming up like it's a surprise, it's been in the code since at least 2002. A 10 year old code section and I bet I write it up on almost every above t-bar inspection.

It's not one of those sections that you understand to mean "if it doesn't say you can't then you can". It is the exact oppisite, "if it doesn't say you can then you can't".

I also don't understand AHJ's that don't want the wires attached to the ceiling grid when the section clearly says, "....shall be secured at both ends." Not really very secure if you have a wire just flopping around up there.
 
cowboyjwc said:
I'm not quite sure why this is even coming up like it's a surprise, it's been in the code since at least 2002. A 10 year old code section and I bet I write it up on almost every above t-bar inspection.

It's not one of those sections that you understand to mean "if it doesn't say you can't then you can". It is the exact oppisite, "if it doesn't say you can then you can't".

I also don't understand AHJ's that don't want the wires attached to the ceiling grid when the section clearly says, "....shall be secured at both ends." Not really very secure if you have a wire just flopping around up there.
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Agreed. There are many wiremen/contractors who argue this one though.
300.11 'Cables and raceways shall not be supported by ceiling grids'. This seems to be the intent.
Unless you know which AHJ will turn up at your job, or there's no timeframe worries, I'd support them. I always did. I can see an argument if they happen to hang from a box to the luminair and not lay on the T-bar lid, but that's about it.
 
cowboyjwc said:
I'm not quite sure why this is even coming up like it's a surprise, it's been in the code since at least 2002. A 10 year old code section and I bet I write it up on almost every above t-bar inspection.

It's not one of those sections that you understand to mean "if it doesn't say you can't then you can". It is the exact oppisite, "if it doesn't say you can then you can't".

I also don't understand AHJ's that don't want the wires attached to the ceiling grid when the section clearly says, "....shall be secured at both ends." Not really very secure if you have a wire just flopping around up there.
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We used the ceiling grid support wire to support MC cable using zip ties in a non fire rated ceiling space to what I think complies with the excption in 300.11 2. The inspector asked to documentation from the manufacturer. They dont have anything in writing to say you cant in the instructions. Just an email that says as long as you dont bend the grid wire or have it resting on the ceiling they dont care one way or the other. So there is nothing to support or deny the use of the exeption
I understand the code says what it says...but it also dosent say what isnt there. So who's to say you cant if it isnt in the book.
 
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craig127 said:
We used the ceiling grid support wire to support MC cable using zip ties in a non fire rated ceiling space to what I think complies with the excption in 300.11 2. The inspector asked to documentation from the manufacturer. They dont have anything in writing to say you cant in the instructions. Just an email that says as long as you dont bend the grid wire or have it resting on the ceiling they dont care one way or the other. So there is nothing to support or deny the use of the exeption
I understand the code says what it says...but it also dosent say what isnt there. QUOTE]

300.11 dosent say you cant use ceiling grid wire to support cables it reads "support wires that do not provide secure support shall not be permitted as sole support....."where" ( not shall") independant support wires are used they shall be secured at both ends. cables and raceways shall not be supported by cieling "grids", the word "wire" isnt there IMO the grid wire provides secure support ans as such it is permited as sole support
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craig127 said:
the word "wire" isnt there IMO the grid wire provides secure support ans as such it is permited as sole support
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And all you have to do now is get your inspector in line with that thinking and your're home free, don't hold your breath though. :D

Roger
 
craig127 said:
craig127 said:
We used the ceiling grid support wire to support MC cable using zip ties in a non fire rated ceiling space to what I think complies with the excption in 300.11 2. The inspector asked to documentation from the manufacturer. They dont have anything in writing to say you cant in the instructions. Just an email that says as long as you dont bend the grid wire or have it resting on the ceiling they dont care one way or the other. So there is nothing to support or deny the use of the exeption
I understand the code says what it says...but it also dosent say what isnt there. QUOTE]

300.11 dosent say you cant use ceiling grid wire to support cables it reads "support wires that do not provide secure support shall not be permitted as sole support....."where" ( not shall") independant support wires are used they shall be secured at both ends. cables and raceways shall not be supported by cieling "grids", the word "wire" isnt there IMO the grid wire provides secure support ans as such it is permited as sole support
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Actually the word wire is there, 300-11(A)(2) says, "Wiring located within the cavity of a non-fire rated floor-ceiling or roof-ceiling assembly shall not be secured to or supported by, the ceiling assembly, including the ceiling support wires."
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What is wrong with 320.30(B)(3)? For lights if can be up to six feet(free).


Here's the twist I've seen in the field, the whip one holed to light...
 
ike5547 said:
That's interesting. I've never heard this before. Is there any documentary evidence to support this?
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Actually I did at one time, but 330.30(D)(2) does allow it, so I will recant that statement for now.:)

I used to live in Chico. Went to John McManus Elementy school from K-3.

Edit: Sorry didn't see cadpoints post. Also I'm in the 2008 NEC, just in case it's different from the 2011
 
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