Page 1 of 2 12 LastLast
Results 1 to 15 of 26

Thread: junction boxes in attic instead of conduit in garage workshop?

  1. #1
    Join Date
    Sep 2017
    Location
    Tempe, AZ
    Posts
    9

    junction boxes in attic instead of conduit in garage workshop?

    Hi everyone,

    I would love to get your input on a hopefully straightforward question. I have a small two-car garage workshop that I want to add about nine new receptacles on three circuits (one circuit per wall) around the whole garage. The garage is already finished with drywall on the walls and ceiling and each receptacle that I'm planning will end up being in it's own stud bay. I have already run all the NM-B from the service entry for the house over to the attic above the garage and am at a decision point:

    I was going to drill down through the top plate in the attic and come down through the wall for the first outlet in the series for each circuit and then move to external conduit on top of the dry wall for the remaining receptacles, but then I started thinking that since I am drilling holes in the top plate anyway, I could just install junction boxes in the attic with three way splits and come down into each stud bay through three top plate holes for each receptacle and have a cleaner look in the shop with all cables running behind the drywall. If I am willing to do the extra attic work is this a good idea? Or would this be bad practice to have several junction boxes up in the attic? Thanks in advance.

  2. #2
    Hard to access splices should be avoided as a fire hazard.

  3. #3
    Join Date
    Jul 2007
    Location
    NE OH
    Posts
    2,615
    Well, by code, jboxes have to be "accessible". Access from the attic is probably OK, but your local inspector has the final word. You could also put the jboxes in the ceiling with blank covers.

  4. #4
    Join Date
    Jan 2010
    Location
    LA & SC neither one is Cali
    Posts
    9,447
    No problem with attic J-boxes as long as they remain accessible and you don't exceed the code maximum for wires in a box, of course, the latter applies to any box anywhere.
    Of all the laws Brandolini's may be the most universally true.

    Deep thought for the day:

    Your bandsaw weighs more when you leave the spring compressed instead of relieving the tension.

  5. #5
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    65,685
    I agree with Van...if they are accessible, then they should be fine. And the method you describe is a cleaner install for those utility outlets. Honestly, I wish I would have used this method for many of my shop circuits because then I wouldn't have had to make sure the J-boxes remained accessible when I put in my shop ceiling a few months ago. That access really looks "not nice" to my anal sensibilities.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  6. #6
    Join Date
    Sep 2017
    Location
    Tempe, AZ
    Posts
    9
    okay, thanks so much guys, just wanted a reality check! The J-boxes will definitely remain accessible and I won't be overfilling them...

  7. #7
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    9,879
    As long as you have those boxes in the attic make sure some of them have an outlet so you can have power for a light or drill up in the attic. You may have to use a 4" box to have enough room for all the wires.
    I ran strings of clear Christmas lights down the ridge beam in my attic for light. bright enough to read a label on a box or look for a leak but I still need a droplight for real work.
    Bil lD

  8. #8
    Join Date
    Sep 2017
    Location
    Tempe, AZ
    Posts
    9
    oh, that's a good idea!

  9. #9
    Join Date
    Apr 2008
    Location
    River Falls WI
    Posts
    490
    When I was cleaning up some of my houses wiring in the attic, many of the existing boxes had no covers. I have no idea if the previous owner did this or not. My basement had buried boxes and clipped ground wires. The trick I used in my Attic for the boxes I still had, was to use a board to raise it above the insulation and install box covers on all of them. Not sure if it was enough height when I had more insulation added a few years back. I have to go up and check this summer, since I think squirrels got in this winter. The advantage of conduit exposed, is that you know where everything is. It is fairly easy to install PVC version, if you do not want to bend conduit. Dan

  10. #10
    Join Date
    Sep 2017
    Location
    Tempe, AZ
    Posts
    9
    Thanks for the reply Dan! That was one thing I was thinking about as a plus for putting the conduit on top of the drywall—being able to see it and access it without clambering around (like a squirrel) in my tiny attic. Yeah, I had a couple of those j-boxes with no covers up in my attic as well...

  11. #11
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    12,298
    Quote Originally Posted by Rick Overson View Post
    oh, that's a good idea!
    One possible idea for a light in the attic. I once went into the attic space in a house to find someone had left a light on, perhaps from months before.

    In my shop I installed a light in the attic space with the switch high on the wall near the access point in the shop. To keep me from accidentally leaving the light on I used a switch with an integral pilot light.

    JKJ

  12. #12
    Join Date
    Jan 2008
    Location
    Western Nebraska
    Posts
    4,680
    Surface mounting the conduit and only one hole through the plate is a lot easier and cheaper if you are paying someone to do it. Individual drops are a lot cleaner install though. It can be a pain to access that plate for holes under low pitch eaves, literally, don't let a roofing nail stab you in the head.

  13. #13
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    65,685
    The caveat for the outlet suggestion is this kinda requires more than one circuit because you need to kill power to work and that would kill the lighting if you only have one for these utility outlets in the shop area. But I'm sure you thought of that! I also recommend "oversize" boxes up there...much easier to work with on initial installation, easier to work on if you need to make changes/additions and as already suggested, leaves space for an outlet. Face the boxes so your outlets are not pointing upward, however, so incidental debris stays out of them.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  14. #14
    Rick,

    Why put the j boxes in the attic? I think drilling through the plate and crawling around in the attic is something I would avoid if I could.

    So I suggest a much simpler way of doing this which I've done in the past:

    Remove the section of drywall above the panel, which give clear access to all the knockouts. Replace the drywall with a piece of plywood, which can be removed easily for a future deal.

    Run flex or conduit to a junction box surface mounted on either the wall or ceiling, and run your circuits from there. Run 3 hots, a neutral and ground to the J box and run your 3 circuits from there. Do everything surface mounted. I really like using the metal flex like this with the wire already in it.

    Another alternative is what the electricians did in my shop which was run several hots in one run of conduit, and pass through certain outlet boxes to the next circuit. This saves even having to use j boxes. Hope I'm explaining this well. IOW, the first wall all the outlet boxes will have 2 hots just passing through, the second wall, 1 and the last hot goes to the last circuit. The neutrals and ground are daisy chained all the way through.

    The only downside to this is you have to use the outlet boxes as j boxes if you ever plan to alter a circuit.

    Hope this makes sense, but as in all things electric my advice is ALWAYS consult an electrician, not a forum!!
    Last edited by Robert Engel; 05-31-2018 at 9:46 AM.

  15. #15
    Join Date
    Apr 2005
    Location
    Central MA
    Posts
    1,584
    Quote Originally Posted by Robert Engel View Post
    ... Run 3 hots, a neutral and ground to the J box and run your 3 circuits from there...!
    DANGER WILL ROBINSON!!! Three hots and a neutral is a recipe for disaster UNLESS they are being fed from a three phase panel and tied to the three poles of a common trip breaker. Unless it’s a typo, this is incredibly reckless advise and in direct violation of the NEC.

    Im a fan of multiwire (Edison) branch circuits for residential shops but I personally would never recommend them to anyone that doesn’t already understand the benefits and limitations. The problem with internet advise like this is that not everyone reading it is able to see the spot the problems. People tend to generally accept that anyone who answers a question knows what they are talking about.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •