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  1. #1
    Join Date
    Aug 2008
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    Default Electric wiring basement

    Hi

    Can anyone tell me what/if the code requirement is for running electrical wiring in a basement perpendicular to the floor joists.

    Can the wire be stapled to the bottom of the floor joist OR do you have to drill through each joist to run the wire ?
    1) If floor joists are exposed
    2) If there is a suspended ceiling


    Thank you in advance
    albanello

  2. #2
    Join Date
    May 2008
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    Pacific Northwet
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    1,589

    Default Re: Electric wiring basement

    If you don't run it through the joists, you'll make it extremely difficult if you ever want to install sheetrock.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

  3. #3
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    Aug 2008
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    Midwest
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    179

    Default Re: Electric wiring basement

    In an unfinished basement:

    When running NM at an angle to the joists, you must drill holes or use a running board. NEC 334.15(C) If you drill holes the bottom edge of the hole must be >1.25" from the bottom of the joist, or you must use nailing plates. NEC 300.4
    http://www.selfhelpforums.com/showthread.php?t=18175

    Above drop-in ceilings:

    When it comes to drop in ceilings, it is only legal to use NM in dwelling units. NEC 334.12 (A) (2) By code, drop in ceiling tiles are considered "exposed work" as they are easily removed. NEC 100 Def. of Accessible.

    Depending on your inspector, he may allow staples, require holes, or if following the code to the letter, may require it in a conduit raceway. NEC 334.15 (B)

    I always drill holes because they are faster than staples, especially if there is more than one cable, and they are less likely to get flagged. And what Fencepost said.
    Last edited by ZZZ; 01-26-2011 at 06:03 PM.
    "Lead by Example"

  4. #4
    Join Date
    Aug 2008
    Posts
    24

    Default Re: Electric wiring basement

    Thank You for your responses

    Fencepost:
    I will not be using drywall on the ceiling but based on ZZZ text I have to drill through the Floor joists anyway.

    ZZZ:
    I was just hoping to save some work and I hate to drill through any structural member at any time if it can be avoided, even if it is only a small hole.

    Thanks again
    albanello

  5. #5
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    Aug 2008
    Location
    Midwest
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    179

    Default Re: Electric wiring basement

    According to the codes you can drill a very large hole through joists without weakening them. I wonld never do it, but you can go up to 1/3 the width of the lumber as long as you keep them 2" from either edge. Notching is the very worst thing you can do and is not allowed at all on engineered lumber. I use a 3/4" or 7/8" bit for most runs, and larger for 6-3 etc. With a Milwaukee hole hawg (any low speed right angle drill will work) and a 6" auger bit with a screw point (ship auger) it will pull itself through without much effort on your part. The smallest you can go for romex is about 1/2" but it is not a good idea because it makes it so difficult to pull you will damage the insulation. A very important tip: Since the wire will pull best when the holes are aligned, snap a chalk line along the bottom edges of the joists, and use a 2-1/2" scrap of wood to mark the distance to the center of the hole to get them all in line. Keep the drill perpendicular to the wood so the hole isn't angled. The slightest angle will make it more difficult to put if you are drilling the smaller size holes, or have more than one cable. Flat spade bits will work you to death, they require constant pressure to feed.

    Also keep your run at least 6" from the ends of the joists to avoid nails and weakening the lumber.

    The best article ever on this was in Family Handyman, which I have, this is a copy of it (from a Chinese website???) http://www.en8848.com.cn/Article/Hom...ing/56864.html
    Last edited by ZZZ; 01-27-2011 at 09:10 AM.
    "Lead by Example"

  6. #6
    Join Date
    Aug 2008
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    24

    Default Re: Electric wiring basement

    ZZZ

    Thanks for the pointers. Unfortunately all I have is a 1/2" flat spade bit. I bought one of the auger bit but it just screwed its self into the wood. I guess my drill does not have enough *****.

    The chalk line is a good idea, sometimes the simplest solution is the one you don't think of. I don't do this for a living so generally I have to sit and think about how/what I am going to do before I do it and then I forget the trick the next time I do that job. Oh well.

    Thanks for the input.
    albanello

    PS the text editor is puting ***** every time I type p o w e r
    Last edited by albanello; 01-27-2011 at 02:08 PM.

  7. #7
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
    Posts
    706

    Default Re: Electric wiring basement

    If you're sure you won't be putting sheetrock on the ceiling later on, just nail a "running board" where you want to run wire at an angle to the floor joists and staple your romex to it.

    thesemi-retiredelectrician.com

  8. #8
    Join Date
    Aug 2008
    Posts
    24

    Default Re: Electric wiring basement

    The Semi-Retired Electric

    Thank you for your response.

    I'm sure I will not be putting up sheetrock. I hate the idea of never being able to see the floor joists again. Normally that is the first place to see termites invading. But for the next person, who may want to put up sheetrock, I went ahead and drilled through the floor joists and ran the wires last weekend.

    Just a note:
    It help to have the drill turning in the correct direction when boring though floor joists ha ha.

    Thanks again
    albanello

  9. #9
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
    Posts
    706

    Default Re: Electric wiring basement

    Same with screws: righty tighty.

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