mc cable in air void with zip ties

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ericsherman37

ericsherman37

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Location
Oregon Coast
So I'm helping wire a new movie theatre. The exterior walls are cinder block, the interior are metal studs. There is a small (like 1") void between them. My journeyman had me run some exit light circuits around the whole perimeter. I'm not sure I approve of the method he had me use to install it (I'm going to keep my mouth shut cause I'm an apprentice, but I'd like to see if anyone has any ideas or opinions on this).

1) He had me run the MC cable in the void between the metal stud wall and the cinder block wall. Is this okay?

2) He gave me a bag of zip ties to hang the MC from the pre-punched holes in the studs. Can't get a drill back there to attach regular MC straps. Are zip ties okay for supporting MC?

mccinderblock.gif
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Cable ties are fine:

330.30 Securing and Supporting.
(A) General. Type MC cable shall be supported and secured by staples, cable ties, straps, hangers, or similar fittings or other approved means designed and installed so as not to damage the cable.
(B) Securing. Unless otherwise provided, cables shall be secured at intervals not exceeding 1.8 m (6 ft). Cables containing four or fewer conductors sized no larger than 10 AWG shall be secured within 300 mm (12 in.) of every box, cabinet, fitting, or other cable termination.
Click to expand...
 
480sparky

480sparky

Senior Member
Location
Iowegia
Pierre C Belarge said:
That is a very common method, I am not sure what your concerns are.
Click to expand...

It sounds like the same method I use for NM when finishing a basement. Instead of drilling holes in all the studs, I just run the NM in the gap between the framing and the foundation.

There are some who say my method of support the cable is not listed, therefore would not pass inspections.

DSC_1892a.jpg
 
infinity

infinity

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Staff member
Location
New Jersey
Occupation
Journeyman Electrician
480sparky said:
It sounds like the same method I use for NM when finishing a basement. Instead of drilling holes in all the studs, I just run the NM in the gap between the framing and the foundation.

There are some who say my method of support the cable is not listed, therefore would not pass inspections.

DSC_1892a.jpg
Click to expand...

Maybe it's me, but a sharp bit and a good drill should be just as fast if not faster than this method, and code compliant. ;)
 
Pierre C Belarge

Pierre C Belarge

Senior Member
Location
Westchester County, New York
Smart $ said:
The main difference is that there are already holes in the metal studs. Why not just pull the MC throught the holes and call it a day???
Click to expand...

Maybe the depth of the metal stud may not be enough to comply with 300.4(D).


480sparky said:
It sounds like the same method I use for NM when finishing a basement. Instead of drilling holes in all the studs, I just run the NM in the gap between the framing and the foundation.

There are some who say my method of support the cable is not listed, therefore would not pass inspections.

DSC_1892a.jpg
Click to expand...


Show me where there is a listing requirement in 334.30.

"...designed and installed so as not to damage the cable, ..."

Designed by who?
and
Your method looks as though it protects the cable from damage
and
...it has been designed, by you.;):cool:
 
Smart $

Smart $

Esteemed Member
Location
Ohio
PetrosA said:
'Cause then you need them plastic bushing thingies, and some brands of MC pull in one direction only. :grin:
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Have never used those plastic bushing thingies.

As to one direction only is a myth. Granted it may be harder to pull in one direction, but not impossible...
 
PetrosA

PetrosA

Senior Member
Location
Lancaster, Pennsylvania
Smart $ said:
Have never used those plastic bushing thingies.

As to one direction only is a myth. Granted it may be harder to pull in one direction, but not impossible...
Click to expand...

True, the wedge-wound stuff can be pulled in both directions, but I hate it when you get 50' through the hole, then it binds and pulls the jacket apart. Or worse yet, pulling it the wrong way through a long wall of metal studs - even with plastic bushings it's a nightmare. It's much simpler to go to the other supply house and get the smooth wound MC :)
 
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C

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
Pierre C Belarge said:
Maybe the depth of the metal stud may not be enough to comply with 300.4(D).
Click to expand...

That doesn't apply IMO. That applies only to cables ran parallel or along the length of the framing, not through it.

Maybe you meant to say 300.4(A)1, but that doesn't apply to steel studs.
 
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