MC CABLE THRU METAL FRAMING MEMBERS

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I HAVE AN ELECTRICAL INSPECTION DEPARTMENT THAT HAS FOR YEARS MISINTERPETED THIS SECTION OF THE CODE. THEY HAVE ASSERTED THAT MC CABLE RUN HORIZONTALLY THRU METAL STUDS HAVE TO HAVE THE INSULATING BUSHINGS INSTALLED IN THE HOLES OF THE METAL STUDS. I BELIEVE THAT THE 2005 CODE HAS ADDRESSED THIS BUT THIS CITY IS STILL WORKING OFF OF THE '96 CODE. I DON'T BELIEVE THEY ARE RIGHT AS THEY REFER TO SECTION 300-4B OF THE '96 CODE. I AM GOING TO TAKE THEM TO TASK ON THIS ONE AS THEY HAVE RECENTLY TURNED DOWN A PROJECT WITH THE MC THRU THE STUDS. ANY COMMENTS THAT WILL HELP?
 

Jhr

Senior Member
Re: MC CABLE THRU METAL FRAMING MEMBERS

THEY REFER TO SECTION 300-4B OF THE '96 CODE.
Can you quote the wording of the 96 code section you are referring to, this would help. The only other code book I have is the 99 and that section refers to Romex cable, why mc cable would need protection from the metal studs I can't see it.

[ February 03, 2006, 01:53 PM: Message edited by: Jhr ]
 

bdarnell

Senior Member
Location
Indianapolis, IN
Occupation
Retired Engineer
Re: MC CABLE THRU METAL FRAMING MEMBERS

I don't have my '96 with me, but '99 300.4(b) refers to NM and ENT, not MC.

Having said that, we had the same issue in Kissimmee, FL with the local AHJ. He made us put bushings in the metal studs for MC. We just did it as it really didn't impact our job cost all that much.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Re: MC CABLE THRU METAL FRAMING MEMBERS

The first thought that popped into my head was why would they even think that you would need a plastic bushing around a metal clad cable going through a metal stud. My second thought was can they read? There is nothing in 300-4B in the 1996 NEC that even comes close to requiring this. :)
 

Minuteman

Senior Member
Re: MC CABLE THRU METAL FRAMING MEMBERS

I have found the inserts to be handy durring the M/C pull. Less drag. So we uses them most of the time to speed things up.
 

iwire

Moderator
Staff member
Location
Massachusetts
Re: MC CABLE THRU METAL FRAMING MEMBERS

Originally posted by Minuteman:
I have found the inserts to be handy durring the M/C pull. Less drag. So we uses them most of the time to speed things up.
They are handy if you are trying to be quite due to working in occupied areas.

Other than that I do not use them. Just pull the cable the right direction, it makes a big difference. :)
 

tshea

Senior Member
Location
Wisconsin
Re: MC CABLE THRU METAL FRAMING MEMBERS

Originally posted by Minuteman:
Yeah, there is a RIGHT direction. Funny though, some guys fight it and take FOREVER.
Hey Boss, I used up those extra grommets for the MC cable run.
Why?
Cable was a b*&^h to pull thru. Grommets made it easier.
Did you try pulling the cable the other way?
What good is that? It'll still get stuck.
1 box grommets $10.00
2 hours labor $200.00
Useless excuse Priceless
 

tkb

Senior Member
Location
MA
Re: MC CABLE THRU METAL FRAMING MEMBERS

Ever try the Greenlee BX stud punch #724?

Greenlee 724

It punches a square hole by piercing the stud and rolling the edges, not punching out a slug.

MC slides very well both ways.

Smaller than the 710 punch and 1/2 the price.

[ February 07, 2006, 08:46 PM: Message edited by: tkb ]
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Re: MC CABLE THRU METAL FRAMING MEMBERS

tkb, my boss actually bought one of those for us to use with NM. It's great for stripping cables for recycling. :D

The journeyman and I looked at it, looked at each other with that "WTF?" look, laughed, pitched it in the back of the trailer to be forgotten forever.

I did pull it out for ENT runs, it did a good job on that.

The romex though, I still get a chuckle out of that one. :D
 

tkb

Senior Member
Location
MA
Re: MC CABLE THRU METAL FRAMING MEMBERS

George,
Using this tool to make holes in metal studs for NM cable is a violation ot 300.4(B)(1).

You would have to use the 710 punch and grommets.

No wonder you had problems with the NM.

It's good for ENT, MC and AC since it gives a rolled edge. The cables pull in both direction with less noise.

It is a strange tool anyways. :)

[ February 08, 2006, 07:41 PM: Message edited by: tkb ]
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Re: MC CABLE THRU METAL FRAMING MEMBERS

Originally posted by tkb:
Using this tool to make holes in metal studs for NM cable is a violation ot 300.4(B)(1).
Right. The codebook says that.

Common sense says it too, without looking it up. :D :p
 
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