Search the forums

Loading

Hole size for romex?

davidmeiland's picture

I need a memory jog on this... the correct drill size for (2) 12/2 romex thru framing. I believe I can run two thru a 7/8" hole but want to be sure it isn't actually 1" that's required. Nothing in my Code Check Electrical about it, and nothing in the dinky electrical code section of the IRC.

(post #102414, reply #1 of 35)

1/2 to 5/8"...


for a single run..



 


 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!


Forget the primal scream, just ROAR!!!


Edited 10/15/2006 12:10 am by IMERC

"Some days it's just not worth chewing through the restraints"

(post #102414, reply #2 of 35)

I don't think any size hole is required, but 3/4 is as big as I would go for 2 12-2.  5/8 will work.

(post #102414, reply #3 of 35)

Yeah, it'll fit through 1/2 or 5/8", but a hole that small makes it a PITA pulling the cable. 3/4" is better.


If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #102414, reply #4 of 35)

Every auger bit my electrician's guys lose has been a 3/4" so that must be his universal size.

;)

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #102414, reply #5 of 35)

Try them new Rigid wood bits...WOW!


I have a slew of old Greenlee and Mils, got the itch to try some thing new, these are the deal.



Spheramid Enterprises Architectural Woodworks


"have the cold, comfortably numb"


For Darcy.

www.richmondrenovationsandrestoration.com  

(post #102414, reply #6 of 35)

I got one of those wood spade bits with the screw in the middle, it will eat some wood.

(post #102414, reply #7 of 35)

Yeah, the cats azz for rough drilling.


Spheramid Enterprises Architectural Woodworks


"have the cold, comfortably numb"


For Darcy.

www.richmondrenovationsandrestoration.com  

(post #102414, reply #23 of 35)

I tried those Rigid bits, they looked like just the thing for me.  I bought a set, broke the 5/8" and the 3/4" bits, returned it for another, did the same thing, returned it for another, then did the same thing again.  That time, I just got my money back.


I was drilling 90 year old 2x4s in my attic.  I wasn't drilling knots or anything, but the screw thread would just refuse to go anymore, and then it would split out the center of the bit- they weren't forged in one piece, like the old ones.  The spot weld was too small to hold up.


Too bad, they were nice bits- I think I got a total of about 11 holes out of 3 sets, and those holes went fast.


zak


"When we build, let us think that we build forever.  Let it not be for present delight nor for present use alone." --John Ruskin


"so it goes"


 

zak

"When we build, let us think that we build forever.  Let it not be for present delight nor for present use alone." --John Ruskin

"so it goes"

 

(post #102414, reply #25 of 35)

Oh crap. I have to install a motion detecter outside light for my firewood pile storage. And, I need to drill through the log wall to run the power feed...8'' of rockhard white oak.


If those bits are that bad, I may rethink my plan, or use the old trusty Craftsman auger bits I have had since I was 15.


Thanks for the heads up, I think.



Spheramid Enterprises Architectural Woodworks


Shooting rubber bands at the Moon

www.richmondrenovationsandrestoration.com  

(post #102414, reply #30 of 35)

Heck, you might as well try the rigid bits.  What have you got to lose?  Every time I took them back, they didn't blink an eye- they just said "do you want to go grab another set, or get your money back?"


I never pass up a good auger bit at a yard sale, though.  With a good sharpening, they go plenty fast for me.  The main draw of the rigid bits was the price- at a set for $15, I figured I didn't have to worry about nails to much, and I could continue to hoard my nice 18" ship augers.


zak


"When we build, let us think that we build forever.  Let it not be for present delight nor for present use alone." --John Ruskin


"so it goes"


 

zak

"When we build, let us think that we build forever.  Let it not be for present delight nor for present use alone." --John Ruskin

"so it goes"

 

(post #102414, reply #31 of 35)

Are any of you guys aware of any hole size requirement per code?  That is, is there a code-mandated limit on the amount of wires you're allowed to pull through a hole of a given size?


Just curious.

(post #102414, reply #32 of 35)

The NEC requirement is generally 40% fill. However the NEC code making panels have a rather poor understanding of arithmatic. What is 2 X 3 X 4 = ?


In the case of wire fill, Romex is cheated because the go with the largest outside diameter and a lot of Romex is oval. So if your Romex is 9/16" wide, you would take 9/32" squared times pi. However these fill limits do not apply to lengths of conduit less than 24". Therefore it doesn't matter unless your stur or joist is more than 24" thick.


As for the copper sleeves, why would they have to be bonded? Also wouldn't Teflon sleeves be even better? But if you insist on copper perhaps you could flare the ends with one of those SnapOn flaring tools.


~Peter

(post #102414, reply #33 of 35)

Yes there is a max. number of wires you can pull through a single hole in a plate or stud.  It's a low number like two or three. 

 


Beer was created so carpenters wouldn't rule the world.

 

Beer was created so carpenters wouldn't rule the world.

(post #102414, reply #34 of 35)

"Yes there is a max. number of wires you can pull through a single hole in a plate or stud. It's a low number like two or three. "

Not here in central VA. I have run lots of romexes through 2 and 2 1/2" holes in deep floor joists and plates in the wall of the service entrance. Not even a request for derateing I guess because the wires were not bundled tightly for 24+".

Frank DuVal

You can never make something foolproof because fools are so ingenious.

Frank DuVal

(post #102414, reply #35 of 35)

It might simply be a difference in how codes are interpreted or inforced locally.  It does make it even more important to have the plumbers and hvac guys in first since the electricans are drilling even more holes.  :-)

 


Beer was created so carpenters wouldn't rule the world.

 

Beer was created so carpenters wouldn't rule the world.

(post #102414, reply #26 of 35)

I have the Rigid.

Not used that much, but maybe 30-50 holes and still going strong.

. William the Geezer, the sequel to Billy the Kid - Shoe

(post #102414, reply #27 of 35)

Same here, except I didn't get through one floor joist. The tip just broke out. I returned it and finished job with spade bit.

(post #102414, reply #8 of 35)

A 2 X 4 is 3 1/2" inches wide. You must have at least 1 1/4" from the edge to your hole. 2 times 1 1/4" = 2 1/2". 3 1/2" - 2 1/2" = 1" = maximal size of your hole.


Smaller holes will work and use less energy and the bits are a little cheaper. But a 1" hole would be easier to pull.


Technical note: a Forstner bit makes the smoothest hole. Use a larghe countersink to chamfer the edges. I would suggest the use of shellac or lacquer to coat the insides of the hole. When dry, coat with teflon lube.


~Peter

(post #102414, reply #9 of 35)

Technical note: a Forstner bit makes the smoothest hole. Use a larghe countersink to chamfer the edges. I would suggest the use of shellac or lacquer to coat the insides of the hole. When dry, coat with teflon lube.


 


you can't be serious..


 


 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!


Forget the primal scream, just ROAR!!!

"Some days it's just not worth chewing through the restraints"

(post #102414, reply #10 of 35)

He is a real hack.

Anyone knows that after coating it wiht lacquer or shellac that you need to rub it out before you pull the wires.

. William the Geezer, the sequel to Billy the Kid - Shoe

(post #102414, reply #12 of 35)

and the sanding up to 22o with rubbing between at least 7 coats..


IIRC he ommitted the champfer part to.....


 


 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!


Forget the primal scream, just ROAR!!!

"Some days it's just not worth chewing through the restraints"

(post #102414, reply #13 of 35)

I resent this "hack" business.


Hacks don't bother with such niceities. But this is the FineHomeBuilding forum. The only fine woodworking we electricians are allowed to do is bore holes in woodstuds.


After a while, this gets boring. So to dress things up to FHB standards this is what I do. Besides, I get paid by the hour. :{


~Peter

(post #102414, reply #17 of 35)

Never, ever " drop the soap" around these guys <G>


 


Dave

(post #102414, reply #18 of 35)

Roar!

when in doubt add garlic

 

(post #102414, reply #19 of 35)

Yeah, the dust nibs will rip the covering off...

ps I love the Milwakee self-feed bits. In fact, I love it so much I have one stuck in the wall right now. Even has an extension on it!

(post #102414, reply #24 of 35)

I just picked up a couple of those Milwaukee self feeders... 2-9/16 and 3-5/8.


KA-CHING! $150.


But they positively eat wood.

(post #102414, reply #14 of 35)

Yeah, you should sand first, with #200.


If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #102414, reply #15 of 35)

Yea, thats how all the electricians do it!

(post #102414, reply #11 of 35)

I really hope ya forgot the (G) there...if not, well....go away.


Spheramid Enterprises Architectural Woodworks


"have the cold, comfortably numb"


For Darcy.

www.richmondrenovationsandrestoration.com  

(post #102414, reply #16 of 35)

You forgot the polished, chromed nail plates, with pull direction indicated, on the front of the studs.

Rather than a chamfer and all the rest of that foo foo stuff you do, I like to thread the hole, and screw in graphite impregnated carbon fiber guide inserts.

Carpe that ol' diem ! ~LisaL

.

It's a small world. Until you have to walk home...