Supporting MC Cable in Acoustical Ceiling

[Armydad]

Recently been called out over improper support of our MC Cable, We have our own ceiling wires supporting our light fixtures and they are also painted for easy identification, we attached our MC to our independent light fixture wire and was told that was a violation and are required to add a additional wire to support the MC...

 

[tom baker]

Not required. The NEC has clarified that the MC fitting is considered support. This change was submitted by the armored cable mfgs association many code cycles ago.
I dont have the code section available right now.

 

[hillbilly1]

I think the OP is referring to mc not related to or not related to the fixture. But I don’t know of anything prohibiting it. It’s independent of the ceiling support.

 

[augie47]

I see it done that way often and had not given it a 2nd thought, however there is wording in 300.11 that might give credibility to such a call:
" Where independent support wires are used, they shall be secured at both ends". .
" An independent means of secure support shall be provided and shall be permitted to be attached to the assembly"

 

[jimport]

I would consider the use of the word independent to simply mean as to not related to ceiling support. To restrict the identified wires to only related wiring or fixture support seems excessive.

 

[jusme123]

Not required. The NEC has clarified that the MC fitting is considered support. This change was submitted by the armored cable mfgs association many code cycles ago.
I dont have the code section available right now.

330.30(D)(3) last sentence

 

[macmikeman]

I often support mc cables not from the existing ceiling suspension wires, but from the same hook they are hanging from that penetrates the concrete of the floor above. I know it's a grey area , but I have read the code about it often enough to be able to argue this fine point of chicanery with precision and win . The code states that you are not allowed to support cables from the existing suspension wires. It does not say you are not allowed to support from a hooked "nail" shot into the ceiling that is meant to support said ceiling wires. Other times I will set a quarter/20 threaded rod and drop anchor and use a bunch of K-12'S or K-16's hanging off that 1/4" rod, with maybe a mineralac hanger at the bottom of it all for one more cable run. Wires have to be secured to the grid. As far as I know, hanging rods do not.

 

[LarryFine]

Other times I will set a quarter/20 threaded rod and drop anchor and use a bunch of K-12'S or K-16's hanging off that 1/4" rod, with maybe a mineralac hanger at the bottom of it all for one more cable run. Wires have to be secured to the grid. As far as I know, hanging rods do not.

I have been called on that. "Supported and secured" includes lateral support, too.

 

[macmikeman]

I have been called on that. "Supported and secured" includes lateral support, too.

Yea, I like to think the cables themselves are the lateral support, but that takes some deep meditation