ECN Forum Forums Code Related Discussion NEC & other Code issues Drilling Holes

I am new to this forum. Could anyone tell me if there is a code other than the 1-1/4" depth for drilling holes in floor joist. I did this lighting for some one in a new addition. The person I did the work for was told by a electrician friend that you can not drill down the center of the beams.I have never hear of this before,neither have any of my fellow coworkers. Any input on this would be helpful. Thanks

I believe it is a CABO rule that holes are to be on the outer thirds of a joist, ie if the joist is 24 feet long the first 8 feet from the tie in walls are ok farther than that you went more than 1/3 of the safe distance.

-Mark-

Be careful with engineered joists.....the rules are different. Follow the instructions that come with the joists.

BOCA has the wood info. don't drill a laminated beam top to bottom or you'll be buying some expensive reconstruction, manufacturers don't allow this bore.
Notches you might as well consider taboo for safety sake.
The 1/3 rule has a few factors associated with it, notches are definitely not allowed in the middle 1/3. Safest place to drill is down the middle of anything, the rule is any floor/ceiling member edge of hole no closer than 2" minimun. A 1 1/8" bit is the biggest you better buy, it let's you drill center of 2x4 just legally, all other structures check into. TGI'S not on edges, only center of particle, must stay 2' off of any termination point, ie; foundation, center support beam where end is cut.
BOCA & CABO have specs for us to follow.

1998 ICC 1 & 2 Family dwelling Code:

Holes in sawn joists: edge of the holes must be at least 2" away from edge of the joist and other holes and notches.


You can never drill down thru a joist. (I think that is waht you did.)

Holes in engineered lumber: follow the directions.

What I did was drilled in the center( length+width). The holes are abover the 2" from bottom. The question is, is it legal to drill a hole in this manner. Western wood product Association gives a good idea that is is.This is only a 7/8" hole.I could not find the info on boca or Icc's website.This is a solid 2*10 joist.

I believe what you were asking about was drilling a hole through the 9 1/2 inch dimension not the 1 1/2 inch dimension. And if so the 1 1/4 rule applies here in Kansas. Most pre-fabed joist use to have knock-outs for plumbing and wiring. ( I don't know if they still do or not) Here most joist are Pre-Fabed 2x4 floor joists. I think this is what you asked, if not I new to the forum but have been reading for sometime and I know someone out there has the answer.

That is correct in 9 1/2". I know there is a 2" rule from the bottom of the joist. I would like to know any other rules apply to a drilled hole.