Bored MC cable holes

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Does MC cable follow the same rules as NM cable when it comes to 'bored' holes (in wood framing)?
300.4 says to have a minimum of 1 1/4" from hole to stud side. (Unless you use a nail plate.)
It also says that rigid, intermediate, and emt are exempt.
It says nothing about MC.
At this, I would assume that MC is treated the same as NM. Am I correct in my assumption?
 

infinity

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Wood with bored hole, yes. If you have metal studs there is no 1.125" requirment for the hole.
 

ritelec

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Jersey
That would include drilling or punching out the stud?

If you get a chance, could you show the reference?


Thanks
 

infinity

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That would include drilling or punching out the stud?

If you get a chance, could you show the reference?


Thanks

Any hole in a metal stud with MC cable. You won't find a reference because there isn't one that requires the 1.25" spacing like with wood studs.
 

Little Bill

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I hope this is not taking the thread off course, but I have a question along the same lines. The 1-1/4" distance for the holes in wooden framing members is also to be applied to NM cable running adjacent to firring strips. In other words, you have to keep the cable 1-1/4" from the edge of the firring strips. Why is that? If the reason is in case the installer misses the firring strip with his screw/nail, who's to say he won't miss it more than 1-1/4"? I just don't see the reason for this rule. But my brain gets "fuzzy" sometimes.:lol:
Someone please help me "un-fuzzy it.:)
 

infinity

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I hope this is not taking the thread off course, but I have a question along the same lines. The 1-1/4" distance for the holes in wooden framing members is also to be applied to NM cable running adjacent to firring strips. In other words, you have to keep the cable 1-1/4" from the edge of the firring strips. Why is that? If the reason is in case the installer misses the firring strip with his screw/nail, who's to say he won't miss it more than 1-1/4"? I just don't see the reason for this rule. But my brain gets "fuzzy" sometimes.:lol:
Someone please help me "un-fuzzy it.:)

That is true. If a 3/4" furring strip is attached to a foundation wall you can run the NM cable 1.25" away from the edge of the strip and strap it to the foundation wall itself.
 

roger

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If the reason is in case the installer misses the firring strip with his screw/nail, who's to say he won't miss it more than 1-1/4"?
And on a similar note, I've also wondered what keeps the sheetrocker from using 1-1/2" or 2" screws if that's what he has in his pouch.


Roger
 

jmellc

Senior Member
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Durham, NC
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Facility Maintenance Tech. Licensed Electrician
Even if rules allowed it, don't make trouble for yourself by running MC near the edge. A screw penetrates it nearly as easily as NM cable. Same with EMT. I have seen drywall tek screws zip right into EMT if they hit square on.
 

dhalleron

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Location
Louisville, KY
On another note, if a screw or nail goes through NM cable, there is a chance it will miss some or all of the conductors and won't short out. I?ve seen this happen.

If a nail or screw goes through MC or BX due to the metal shield and twist of the conductors, it will most likely trip a breaker. I?ve found this problem a few times. My brother was nailing down some loose boards in a second floor bedroom of his old farmhouse when he hit a BX cable.
 

ritelec

Senior Member
Location
Jersey
On another note, if a screw or nail goes through NM cable, there is a chance it will miss some or all of the conductors and won't short out. I?ve seen this happen.

Just to mention...................I was doing some wiring years ago, replacing and adding circuits (old house). There was a circuit of nm 2 wire running through the basement

which was supported (secured) by running roofing nails through the center (ground).

Just had to mention that after seeing what you wrote dhelleron.
 

readydave8

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Location
Clarkesville, Georgia
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electrician
Just to mention...................I was doing some wiring years ago, replacing and adding circuits (old house). There was a circuit of nm 2 wire running through the basement

which was supported (secured) by running roofing nails through the center (ground).

Just had to mention that after seeing what you wrote dhelleron.
I saw something similiar but instead of nm they used lamp cord.
 

Little Bill

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Tennessee NEC:2017
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Semi-Retired Electrician
That is true. If a 3/4" furring strip is attached to a foundation wall you can run the NM cable 1.25" away from the edge of the strip and strap it to the foundation wall itself.

My question is why this rule for firring strips? I understand keeping a hole in the center of a stud (1-1/4" from edge) I just don't see the logic for the 1-1/4" from edge of firring strips.
 

infinity

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My question is why this rule for firring strips? I understand keeping a hole in the center of a stud (1-1/4" from edge) I just don't see the logic for the 1-1/4" from edge of firring strips.

Good question. Why the code requires 1.25" from the edge when using furring strips is beyond me.
 
I have been taught this trade from someone who often said "that is good enough". Without giving reference to the code in way, shape, or form. Now that I am on my own, I am finding out that "that is good enough" is NOT GOOD at all. I am diligent in finding out the RIGHT way. This forum is a gold mine of help and information. After you reference the correct code and explain things, things become clear. Just reading code by itself can be confusing to-say-the-least.

PS: I HAVE been hit with drywallers driving screws into my NM cables also have had drywallers cut wires in boxes with poor drywall cutting techniques.

I sincerely thank you one-and-all for everything.
 

ritelec

Senior Member
Location
Jersey
I have been taught this trade from someone who often said "that is good enough". Without giving reference to the code in way, shape, or form. Now that I am on my own, I am finding out that "that is good enough" is NOT GOOD at all.

Thanks funny!!! (your last sentence)

There was also do as I say and not as I do.



This forum is a gold mine of help and information. After you reference the correct code and explain things, things become clear. Just reading code by itself can be confusing to-say-the-least.

au contraire.........................I find most here don't answer your questions per say. But make you work for it. Sometimes aggravating but much better overall.
 

infinity

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New Jersey
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Journeyman Electrician
T
au contraire.........................I find most here don't answer your questions per say. But make you work for it. Sometimes aggravating but much better overall.

You could ask nicely. :D

Actually there is something to be said for looking up certain things on your own. Obviously for the guys doing homework giving out the answers doesn't help much. ;)
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
I have been taught this trade from someone who often said "that is good enough". Without giving reference to the code in way, shape, or form. Now that I am on my own, I am finding out that "that is good enough" is NOT GOOD at all. I am diligent in finding out the RIGHT way. This forum is a gold mine of help and information. After you reference the correct code and explain things, things become clear. Just reading code by itself can be confusing to-say-the-least.

PS: I HAVE been hit with drywallers driving screws into my NM cables also have had drywallers cut wires in boxes with poor drywall cutting techniques.

I sincerely thank you one-and-all for everything.

I was generally taught pretty well, but I was taught the same error by several guys, back in the 70's. They would all enter a flush mounted panel without NM connectors when adding circuits. They would pop a KO and fish a wire from attic or crawl space directly through it. They would use a connector if the panel edge was open a bit but not otherwise. Then again, there were not as many 1 piece plastic connectors around at the time. But I never liked that. Now, we have several types of snap in connectors that are easier to use.

You are right, this forum is great. Any issue you think of, someone here has dealt with it.
 
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