Next to my meter I have a square d all-in-one combination service entrance device with a service disconnect breaker and a sub panel breaker that must be going to my indoors panel, see attached images. I'd like to add a 15A or 20A breaker for an additional circuit close to the outdoors disconnect panel. Can I do it?

Some similar questions are:

Can a breaker be added to the main disconnect panel?

Can I add a sub-panel near the main disconnect outside my house?

Add circuit off main disconnect or sub-panel required?



From those it sounds like it should be possible but I'd like a confirmation for my specific setup. Thanks!

square d all-in-one combination service entrance device sticker square d all-in-one combination service entrance device service disconnect sub panel indoors panel indoors panel cover

  • 1
    Not only great job with research, but great job with supplying pics!
    – FreeMan
    Dec 1, 2020 at 13:20

2 Answers 2


First of all, congrats, you did a great job researching before asking the question. That's expected of participants here and you did that.

To answer your question, yes, there shouldn't be any reason you can't add a breaker to the outdoor combi box. Others here might chime in with local code issues, but I doubt it. If it makes you more comfortable, turn off the main breaker to shut off power to the buss. Remove the cover, clip the new breaker in place, twist out the cover for that space and wire up the outdoor circuit using conduit and THHN/THWN or UF (UF is hard to work with!), NM (Romex) isn't legal in outdoor installations, even if in conduit.

I don't want to be a dick here, but this is a pretty basic question indicating a basic unfamiliarity with simple wiring. While this is a DIY Home Improvement site, remember that improperly installed electrical circuits can be dangerous. You might want to grab a book at HD or Lowes on basic wiring principles. Again, I really don't want to be rude or condescending, you might actually enjoy reading about basic wiring and how to do it right. Take care and stay safe.

  • 2
    I think OP's question revolved around the fact that it is the main disconnect panel, and whether that would entail anything beyond what would be required for adding a breaker to a "normal" (for lack of a better word) panel.
    – SteveSh
    Dec 1, 2020 at 13:03
  • Re: 3rd paragraph: Eh... I've asked some pretty basic questions that I probably could have learned the answer to on my own. Sometimes, it's just good to get an "official" nod from others more experienced. I do get your point, though - always good to cover bases. Like #12 wire for a 20 amp breaker and #12 or #14 for a 15 amp breaker. ;)
    – FreeMan
    Dec 1, 2020 at 13:23
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    @FreeMan Gotcha. I hear what you are saying, but when I see a question as basic as the OP's, it worries me about what else they "don't know what they don't know". Glad he did ask here for help. That's good. There are lots of ways to hook things up that work, but aren't safe or code compliant. That's why I suggested the OP get a basic wiring book and read up. Take care and stay safe! Dec 1, 2020 at 15:54
  • pssst... you did get my vote, even before your response. ;)
    – FreeMan
    Dec 1, 2020 at 16:00
  • @FreeMan !No I don't know how to tell who voted for what here. I've only bee on SE since the beginning of the year and still learning. Love the site, love contributing, love learning from others . Dec 1, 2020 at 16:03

Outside panel

You know around this place, the top advice is "Get a really BIG panel". They did that and then some on the outside... that is a "16/24" panel, meaning it has 8 spaces (below the main) to accommodate standard breakers, and 8 more spaces (above) that will accommodate either standard breakers or "double-stuffs". You can tell this from the panel diagram in the labeling. Currently the bottom 2 spaces are being used for your house feed, and the rest of the panel is wide open.

Looks legit to me. I don't see any problem placing circuits out here.

Use Square D "HOMeline" breakers only. Do not use any other type. (NEC 110.3(B)). It's legal to use any space in the panel, except:

  • Don't get your hopes up on using double-stuffs much; most new circuits require AFCI or GFCI and those don't exist in double-stuff.
  • For aesthetic reasons, I'd suggest using the lowest available space. Most people stumbling onto an unfamiliar panel expect the main breaker on top, then a gap between main and other breakers. The usual "stranger user" is a First Responder (e.g. Fire Department).

Indoor panel

The indoor panel is another 16/24 (16 spaces with 8 spaces allowed for double-stuffs). Now that you know what to look for in the panel labeling, see a problem?

The spaces allowed for double-stuffs are on the bottom half. Yet, there's one in the upper right. Doesn't belong there.

That panel takes Murray (now Siemens) breakers, and they all look correct for the panel.

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