Return to the Electrical Wiring Forum | Post a Follow-Up

multi-branch j-box for residential

Posted by dgeist (My Page) on
Mon, Feb 27, 12 at 14:45

I'm installing a new breaker sub-panel that is flush-mount on the inside of a finished garage wall. The back and sides could be accessible from the utility room behind (standard 2x4 wall). Per my local code office, I'll need to have the stud bay behind the panel and adjacent framing to the sides, above, and below, drywalled to meet fire code.

I'd like to run a series of conduits from the knock-outs on the panel to either one large or a series of smaller j-boxes that are accessible in the utility room. This will allow me to fish romex lines into the panel as I migrate them from the original main panel and have a proper junction point if the NM lines aren't long enough or if I want to transition to individual conductors inside the conduits and panel to save space.

Alternatively, for branch lines that don't require a junction, I can simply bore out alignment holes for the conduits in the framing and run the NM lines straight in (with abrasion protection) or cap the conduit if unsued. Are there restrictions on conductors for multiple branches running in the same conduit (other than the obligatory GFCI hot-tub/pool stuff)?

Does this all seem reasonable and have others done/seen anything similar? I may be over-thinking the problem, but I want to leave the panel flush mounted in the garage and reasonably "future-proof" for circuit upgrades/changes without having to re-do the drywall every time.


Follow-Up Postings:

RE: multi-branch j-box for residential

I don't see anything particularly wrong. If there's a place that the NM cable reaches now (like where the old pane was), it might just be easier to put one larger box in than lots of little ones. In fact, you can use the box that contained the old panel (just gut insides) if you like.

If you're talking short pieces (less than a foot) of conduit to get physical protection through the framing, there's no restriction on mixing circuits within.
As always, every conduit, knockout, etc... has to use the proper fitting for the type of enclosure and the wire you're running through it.

The other option if I understand your issues is to cover the area below the panel with something removable (might have to be metal).

RE: multi-branch j-box for residential

Thanks for the response. I thought about making the current main panel a big j-box, except it's the original main disconnect for the house and after I have the subpanel in, I'll be having a new service and meter/main installed at the other end of the house and that panel location will by concealed by cabinetry due to renovation.

The current main panel is actually FARTHER from most of the branch runs than the new sub location, so the length of available contiguous NM should not be an issue. I'll be pulling down the walls/ceiling to renovate anyway, so some creative routing and careful joist drilling is all that should be needed there.

The door idea is interesting. Does anyone make tiny fire-rated doors (gnomes-R-us, perhaps... :)

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Electrical Wiring Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here