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Plumbing supply line and electric panel same studbay code issues?

ChrisInIllinois | Posted in Building Code Questions on

I have a lot of projects going on, and a contractor to keep up with. I have read so many codes and blogs, but still can’t find stuff readily when I need it. I’m hoping some can help.

I got a wet wall with the main disconnect panel in it. At there is no pipe on that stuff Bay. I recall some type of code for running or not running pipe in the same Bay.

It would be 4 pex lines, they would be under the panel not above. It’s 4 less holes in the bottom plate, it’s the last 4 that need done. I can sleeve them if need be.

Just thought I would get input first, before I waste 2 more hours reading and digging in the code book.


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  1. jberks | | #1

    I don't know the electrical code by heart... But running plumbing next to an electrical panel is just not good practice.

    And what do you mean by a wet wall? I'm taking it as you have an electrical panel within a wall of a shower... if that's the case.. I'd say that's a bad idea. just my opinion. Also certainly not code. At least what I know with the Canadian electrical code, you can't have a panel in the bathroom.

  2. ChrisInIllinois | | #2

    Wet wall, my understanding is a wall that has plumbing, but more over on both sides.

    My wetwall is the wall that sperates the bathroom from the mechanical/laundy.

    My panel is basicly behind the toilet, but In The mechanical room. That's 2 studbays from the bath shower combo.

    I don't like it but it's stuck there until an add-on or major electrical overhaul.

  3. Expert Member
    Peter Engle | | #3

    NEC article 110.26 lists working space requirements. You must have a working space at least 30" wide and 3' deep in front of the panel, starting at the front face of the panel. The space does not have to be centered on the panel, but the panel must be entirely within the space. This means that one side of the working space can be flush with the edge of the panel. If the toilet is in that space, that's a no-no.

    There are also limits to plumbing and other utilities above and below panels, but I can't find that right now - my online NEC isn't working right now. I know that plumbing cannot be within the working space, but I'm not sure about locating pipes above or below the panel itself.

  4. Expert Member
    BILL WICHERS | | #4

    A typical breaker box will just barely fit between 16” studs in a 2x4 wall. The box (called a “tub” in trade lingo) will completely fill the stud cavity in a 2x4 wall, for the entire height of the panel. You can’t run anything behind the panel, it just won’t fit. If you have a 2x6 wall, I suppose you could physically fit cables/pipes behind the panel, but I wouldn’t recommend doing that.

    The code clearances, the so called “dead front clearance” Peter mentioned is to ensure there is working space in front of the panel. The basic idea is to allow enough space for an electrical to physically fit to be able to access and work on the panel. You need to keep the area clear for 3 feet out from the front of the panel, from the floor to the ceiling.

    Regarding running plumbing in the same stud cavity as electric wiring, I’m not aware of any code that says you can’t (there may be local codes in some places though), but it’s something you should try to avoid doing. I would absolutely NOT install an electrical panel in the same wall with plumbing, or on the opposite side of a wall from a shower or bathtub. I would not install an electrical panel in a bathroom either. If nothing else, the elevated humidity is not going to be good for the life of the components in the panel.

    It’s best to installed a breaker box indoors, in conditioned space. Basements, mud rooms, utility closets, all are good options. Try to avoid installing them outdoors, and garages aren’t great places either. In not case should an electric panel ever be installed in an area where there is a good chance it could get wet.


  5. Expert Member
    Peter Engle | | #5

    In addition to the working space, NEC requires "dedicated space" around electrical equipment, including panels. The "dedicated space" extends for the depth and width of the panel. No foreign utilities (like plumbing) can be installed above or below the panel within this dedicated space, from the floor to a point 6' above the panel, or to the structural ceiling, whichever is lower.

    This section prohibits piping running above or below the panel itself, within the same stud bay, unless the piping was more than 6' above the panel, and protection was provided so that the panel could not be damaged by leakage from the piping.

    1. ChrisInIllinois | | #6

      I think that's what I'm thinking about, where did you find that info Peter?

      Bill, the pipe would be under the box near the floor not behind.

      Also the box is in the laundry room, not the bathroom, they share a common wall. The box is installed in the laundry room at the same place the toilet is in the bath. So not same room, just trying to clear that up :)

      Thanks everyone.

      1. Expert Member
      2. Expert Member
        BILL WICHERS | | #8

        The drawing in the link Akos posted is perfect for showing what you need to know.

        I’d be ok with the panel in the laundry room as long as it’s away from the sink and/or washer. You should really try to keep the clear space in front of the panel too. In a commercial building they’d probably make you post a “no storage” sign on the door. The way to think about this is “if a breaker needs to be reset, can I get to the panel to fix it?” The answer should always be “yes, easily”.


      3. ar_t | | #13

        Chris, you said you didn't want to spend extra time looking up the code. Take the advice and do it the right way.

  6. Expert Member
    Akos | | #9

    I think if you surface mount the panel, then you can have plumbing in the cavity behind it. I would check the exact wording though.

  7. ChrisInIllinois | | #10

    Simple enough, solved my supply running problems, open up another. The toilet supply is in that wall. I will be relocating or looking for a grand father clause. I don't like either but it is what is, I will have to make it work.

    Thanks everyone for your time

    1. Expert Member
      BILL WICHERS | | #11

      If the pipe for the toilet is only in the lower part of the wall, try adding some horizontal blocking right above it. This doesn’t solve the code issue, but if that pipe ever does let go and spray water, at least the blocking will limit the chances of the water getting sprayed up into the electrical panel.


  8. gusfhb | | #12

    I recall I had to build a box to cover my water meter as it was close enough that an electrician working on the panel might come in contact with it.

    Obviously plumbing and electricity run through walls next to each other all the time.
    It is really the safety of an electrician working on the system that was in the mind of the inspector in my case.

  9. ChrisInIllinois | | #14

    It has made things a little bit more complex, but I have moved the supply for the for the toilet over a stud bay. Not the end of the world, just on the wrong side for a neat looking supply. small patch to the drywall.

    1. Expert Member
      BILL WICHERS | | #15

      It’s probably too late for you now, but sometimes it’s best to route the supply up from the floor and avoid the wall altogether. This is pretty easy to do if you have an unfinished basement or crawlspace under the floor.


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