I am getting ready to rough in electrical but before I started drilling all willy nilly through the I joists I wanted to ask if the holes had to be a certain distance away from the end of I joists? I attached a pic for reference thank you! 
Electrical through I joists question
- Thread starter anomm701
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Wiz02
Well-known member
This may help
professional-electrician.com
Cutting Notches and Drilling Holes in Joists
Cutting notches and drilling holes in joists As part of any new installation work or a re-wire, a cable, trunking or cable tray sometimes has to pass through an element of building construction, such
professional-electrician.com
WNYflyer
Well-known member
Get the installation instructions for your particular product. If you don’t know your exact product I’m sure you can get reasonable recommendations from similar products.
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CraigStu
Well-known member
Wiz02's link is a big help. I had always heard drill in the vertical center of a horizontal beam. The top half compresses under load and the bottom half stretches under load. So holes go in the center where neither happens.
Thank you
Chris705
Well-known member
If that is an exterior wall & the I-joist support a second story I am pretty sure there should be vertical 2x material acting as squash blocks at the ends of all I-joists. Then electric could be roughed through the 2x material
Jeff C
Well-known member
There should be a knockout hole pre-pressed about every foot. Just look for the outline of one of these closest to the end. Quick note though, they are not very friendly when it comes to knocking them out. Easiest way to knock them out is to hit them with the claw end on a ripping hammer.
These I joists don't have those I had to drill each hole
Jeff C
Well-known member
Well that stinks. I’ve never seen any without them.
Innovate1
Well-known member
There is also shear stress on the center of the web. So saying nothing happens in the center isn't really true. If you look at the requirements for holes in dimensional lumber they are allowed in the middle third where the shear stress is lower. In the exact center, end to end, it is zero. At the ends it is highest. The linked document says no holes in the center of the span which makes no sense from a mechanical strength point of view. Here's a link more in line with what I have seen multiple places but keep in mind this is for dimensional lumber.
https://buildingadvisor.com/notching-and-boring-joists/
If you are making small holes I don't think it really matters but there may be rules I am not aware of. Best to check the manufacturers recommendations and local AHJ requirements. So areas are more particular about such details than others.
Just 1" holes in. A 14" I beam not anything wild
