ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Recent Posts
240V only in a home and NEC?
by HotLine1 - 05/14/24 03:41 PM
Electricians revenge
by gfretwell - 05/09/24 08:24 PM
Safety at heights?
by gfretwell - 04/23/24 03:03 PM
Old low volt E10 sockets - supplier or alternative
by gfretwell - 04/21/24 11:20 AM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
1 members (Scott35), 34 guests, and 10 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#80261 03/23/02 11:47 PM
Joined: Mar 2002
Posts: 125
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

Stay up to Code with the Latest NEC:

>> 2023 NEC & Related Reference & Exam Prep
2023 NEC & Related Reference & Study Guides

Pass Your Exam the FIRST TIME with the Latest NEC & Exam Prep

>> 2020 NEC & Related Reference & Study Guides

#80262 03/24/02 08:41 AM
Joined: Nov 2001
Posts: 280
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.


#80263 03/24/02 02:05 PM
Joined: Apr 2001
Posts: 507
Be careful with engineered joists.....the rules are different. Follow the instructions that come with the joists.

#80264 03/24/02 09:44 PM
Joined: Mar 2002
Posts: 53
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.

#80265 03/25/02 12:07 PM
Joined: Feb 2002
Posts: 375
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.

#80266 03/25/02 06:59 PM
Joined: Mar 2002
Posts: 125
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.

#80267 03/25/02 07:31 PM
Joined: Mar 2002
Posts: 19
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.

#80268 03/25/02 10:21 PM
Joined: Mar 2002
Posts: 125
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.

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5