ceiling joists and how to run new circuit wire

chris2009

15 years ago

kitchen remodel continues...my electrician indicated the best path to get new circuit wire from the garage (sub panel) to the kitchen. Basically, it has to run across the width of the dining room ceiling next door.

We thought that the joists ran in our favor, but alas, they do not. That means drilling through 9 joists to get to the kitchen.

Two questions: first, is it best to cut the ceiling drywall in a single shape that covers the entire width of the room? That way, re-installing it and patching would likely be a little easier.

Second, is it alright (aka to code) to notch the bottom the the joists and cover with metal plates, or is drilling through the middle of each joist the only way to satisfy code?

thanks

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Comments (10)

randy427
15 years ago
Do NOT notch the bottom of the joists. This weakens them and makes the floor above more prone to bounce and reduces the allowable loading.
Drilling holes in the center of the joists, in the center 1/3 of the spans, is the way to go.

I would say that cutting the ceiling board in a shape that minimizes the cut is preferable. When patching it, I would use drywall screws to secure both the old and new sheetrock at every joist.
gblentz
15 years ago
I'll answer the second question first.

You should NOT notch the face of the joists if at all avoidable. Doing so compromises the joist's strength significantly more than drilling through the mid-section. The nearest point of the hole must be at least 1.25" from the face of the joist. If you can't comply with the 1.25" spec, then metal plates must be used.

As for your first question: One of the techniques electricians use when rewiring along a wall is to cut out a 12" or so strip of drywall for easier access to the old wiring, boxes, wire staples, etc. This also gives a direct view of anything that might be in the way, such as pipes or other wiring. Since you only need to drill a 3/4" or so hole through your joists, you could probably get by with removing a narrower strip.
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If you were going to attach it, and if code doesn't care, I'd suggest you attach it to the joists above. I say this because i think it's more likely that you or someone else would want to raise or replace the ceiling (or even a section of it--especially in the basement, where ceilings can be sort of low), and the romex might be in the way. But it would be less likely that anyone will mess with the floor. I also suggest that if laying the romex on top of the framing is acceptable to code, that you should provide plenty of slack--again, so that someone could come along later and raise the ceiling by 6 inches without having to redo the wiring. I have a place where my licensed electrician suggests that we run wire over the kitchen cabinets, inside the soffit. He suggests this because then we don't have to deal with trying to work inside that space to attach it--cabinets are a pain to take down, space is small and too high to be easy to work in, etc. Because there is a very strong likelihood that someone might take *out* the soffit I put in, and because this is wiring that involves the circuit-breaker panel, they REALLY arent going to want to re-address the whole thing. I'm going to ask him to be sure there's enough slack that someone later could shift that flexible conduit all the way to the back, or up against the ceiling, etc., at a later date without having to rewire. It's like a haircut: you can always cut it shorter pretty easily (if you can get to a junction box on either end easily, you can shorten it there). "Cutting it longer" is impossible, and w/ electrical, you can't just splice it any old where you'd like to, since you have to have a junction box at the splice.
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Cost-Effective Solutions
15 years ago
The advice previously given is absolutely correct, so I have only one other small bit of advice. Before cutting into that ceiling drywall, measure and mark at both ends for both sides (to keep the opening sides parallel), then snap a chalkline on each side. This will simplify sizing and installing the patching drywall segment when you're ready to close things up, since cutting on the lines will mean a straight-sided patch (much easier to cut and fit).

If this job is being done with permits (as it should be), don't close up the ceiling until the Inspector has seen and approved the electrical wiring installed there. Otherwise, he COULD insist that you tear out your ceiling patch so he CAN inspect the work.
chris2009
Original Author
15 years ago
thanks for all the good advice. regarding the drywall - I just had a thought (it's rare, but it happens)...wouldn't the drywall be screwed to each and every joist, therefore, I couldn't really do a cut that spans the entire width of the room, as the drywall wouldn't "fall" away.

Does that make some sense? therefore, I basically have to cut a box out between all 9 joists - yes?
Ron Natalie
15 years ago
Depends if there were any screws/nails in the section that you cut out. If there are, you'll have to pull down the drywall rather than expecting it to just fall for you and then remove any remaining screws/nails.
hendricus
15 years ago
"therefore, I basically have to cut a box out between all 9 joists - yes? "

If you do that you have nothing to fasten new drywall to. Cut the full length, rip out the old, replace with new, tape and mud. One sheet of drywall will do 32 feet when cut 12" wide. Add some tape and mud and you're still under 20 bucks.
chris2009
Original Author
15 years ago
I usually use 1x2's to screw back in and fasten to the existing, surrounding drywall. You can't even believe the finish that's on the existing ceiling drywall - it's too ridiculous to explain, suffice to say it would be difficult to match but easy to patch. Honestly, I'd rather just rip it all out.

So everyone agrees that at least 1.25" from the low-hanging point on the joist is a code accepted everywhere in the U.S.? The hole will likely be 1", as I need to ram 4 circuits through.
brickeyee
15 years ago
"The hole will likely be 1", as I need to ram 4 circuits through."

Drill two smaller holes.
You could also consider running multiwire circuits and would only need two runs of 3 conductor cable them.

Three conductor cable is also slightly smaller than 2 conductor in NM, and the more rounded shape make it easier to pull.
itsunclebill
15 years ago
The basic rules for drilling joists:

The edges of the hole should not be closer than 2 inches from the edge of the joist. The 1-1/4 measurement is the electrical code requirement, the 2 inch measurement is recommended by the lumber industry and enforced by many building codes.

The diameter of the hole may not be more than 1/3 of the ACTUAL height of the joist.

Holes should be be 3 hole diameters apart. ( a 1 inch hole needs 3 inches between hole edges.)
chris2009
Original Author
15 years ago
Thank's, itsunclebill, that is quite the info I was looking for.

ceiling joists and how to run new circuit wire

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ceiling joists and how to run new circuit wire

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