Carlon box clearance

S'mise

Senior Member
Location
Michigan
I don't do much residential work so forgive a dumb question.
How can the larger capacity boxes comply with the 1 1/4" clearance requirement (from edge of stud). For instance, a carlon box is almost as deep as the with of a 2x4 stud, and the nm cable is right next to the drywall. ?
 

S'mise

Senior Member
Location
Michigan


This is not a pic of the larger box I'm referring to, but as you can see, The cable is designed to enter the box in the extreme back.
 
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infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
The 1.25" spacing is measured from the front edge of the stud back towards the center or 1.25" away from the stud. If the NM cable is more than 1.25" away from the stud it can touch the drywall. So the question is what about the cable entering the KO right next to the stud but less than 1.25" from the stud face or the drywall?
 

edward

Senior Member
This has been discussed here but i don't believe a conclusion has been met. You really can't do much when installing the cable in the box. If you really want to protect the cables you can install a large 6"x6" steel protective plate behind the box.

As mentioned by Jumper, I wouldn't worry about it.
 

S'mise

Senior Member
Location
Michigan
Thanks guys. I don't mean to nit pick, but seems odd to me that the 1 1/4" spacing is ignored where cable enters the box.

Yes, I could install a protective plate, but I think nema should require a large box to be designed where the cable would enter closer to the center.

I guess, If it's OK with most inspectors, its OK with me. :)
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Electrician
I believe the spacing is meant for where the cable passes through the stud. It's intent was to prevent nails or drywall screws from hitting the cable when driven into the studs.

If you think the "rockers" are far sighted, then you use nail plates!:cool:
 

edward

Senior Member
I believe the spacing is meant for where the cable passes through the stud. It's intent was to prevent nails or drywall screws from hitting the cable when driven into the studs.

If you think the "rockers" are far sighted, then you use nail plates!:cool:
Also when the cable is running parallel to framing members it must be 1.25" away from the edge.

I have seen so many nails, screws that have barely missed the cable. Sometimes you just can't protect every installation.
 

JDB3

Senior Member
I had one home owner use 16 penny nails driven into the sheetrock / studs to support a small shelving unit. The only thing that would protect anything in the wall would have been 1/2" steel plate! The same homeowner used on of his wife's end tables as a saw horse & (yep) sawed into the table. :happysad:
 

kwired

Electron manager
Location
NE Nebraska
It would seem that if this were a big enough issue it would have been resolved long ago, and they would not make these boxes with a cable entry point within 1.25 inches of the side that attaches to the stud. JMO.
 
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