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I am working on a plan for a kitchen remodel. The existing range is natural gas powered so it doesn't have a dedicated circuit (It's just plugged into a 15 or 20amp outlet). Other existing wiring includes a dedicated microwave circuit (15amp breaker but need to check wire gauge). This one I suppose can be used for the fridge (since the fridge currently doesn't seem to have a dedicated breaker).

The oven/microwave combination model I am looking at is KitchenAid KOCE500EBS (KOCE500E model, the BS is just a color code) or similar. The installation manual has these electrical requirements. Electrical connection requirements

My breaker box has a 200A main breaker but I am basically out of room. There is a sub-panel wired right next to it (with a 40A double breaker) that I added for laundry and it has room for 4 single breakers.

What options do I have here? I'm thinking the best approach would be to offload a couple of 15amp circuits marked with red rectangle on the photo (provided I have enough slack - which I should for those bottom breakers) and wire them into a sub-panel. This would free up 2 neighboring boxes in the main panel for a double 40A breaker. Is this a good solution? If I cannot relocate those two 15amp breakers, can I wire for the oven from the sub-panel or do I need to beef up the sub-panel circuit (and by how much), since it already has washer/dryer? Should I be using an 8 AWG or 6 AWG wire to cover me for any future upgrades (say double oven)?

Thanks so much! Dave

The photos of the panels are shown below.

Both panelsSub panelMain panelsub-panel wiring

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  • Welcome to Home Improvement! If you'll take the tour and read through the help center, especially the "how to ask", you'll see that that this is a Q&A board, not a general discussion forum, and that we're looking for one question per question. It's really hard to answer a bunch of questions all in one shot like this within the format laid out. Your "and finally" and "final question" questions should probably be carved off into their own questions - nobody will look down on your for posting several questions. – FreeMan Jun 30 at 10:55
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    Thank you for your guidance. I removed the extra questions. I did leave a question about the wire as I felt it directly pertained to the specific installation and it's power requirements. – David Jun 30 at 13:53
  • Are you maximizing for “cheap/bare legal minimum” or “convenience/happiness of the chef”? – Harper - Reinstate Monica Jun 30 at 15:43
  • Definitely for the latter, but it may be possible to achieve both with my set-up. I will need new wiring to the oven combo no matter what, but the question is whether existing boxes can accommodate the extra circuit. – David Jun 30 at 15:47
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Upgrade that tiny sub-panel. For under $200 you should be able to get a 30-space Eaton panel that will let you re-use all the breakers in your existing 8-space Eaton panel, plus wire and sub-feed lugs for your Siemens main panel. Speaking of which, that BR240 breaker in your main panel that feeds the pictured sub-panel is an alien - it does not belong in there. It may seem to fit, but bus stabs and breaker jaws have subtly different shapes and mixing incompatible types can lead to arcing and bus damage. If you keep the sub-panel as is, you need to replace that with a QP240.

Note, if you replace your sub-panel with a bigger Eaton unit, you can recycle that BR240 by moving it into the sub-panel and use it to feed the new oven.

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  • Thanks. Not sure whether the electrician I hired was not knowledgeable or just lazy to use that breaker there. Thinking it's the latter - probably whatever he had at his hands because there is no excuse not to put a correct $10 breaker there. He was the one to put that sub-panel in. – David Jun 30 at 16:25
  • With your suggestion of 30-space sub-panel, I am thinking model BR3030B100V should suffice. What kind of wire and breaker would I run from Siemens main panel? I'm thinking 3-3-3-5 SER copper cable and a QP260 breaker. – David Jun 30 at 16:37
  • Yeah you could do that for a lot cheaper than $200. Panels/spaces are cheap. I would expect under $100 and to see some “bonus breakers” come with the deal, including possibly a GFCI or AFCI. The electrician did literally follow my “End the subpanel upgrade with 50% of spaces free” rule of thumb, but I generally aim higher than 8 spaces lol... – Harper - Reinstate Monica Jun 30 at 16:52
  • @David for adjacent subpanels, you would link the panels with an EMT conduit nipple (or several) which takes care of ground. Then run 3 THHN/XHHW individual wires through the nipple. No reason to fuss with a balky cable like that. And if you’re running #3 Cu, better to breaker for 100A since #3 Cu can support that no problem. If you only wanted 60A, you could run #6 THHN, but you can breaker that at 70A. – Harper - Reinstate Monica Jun 30 at 16:53
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Wow, whoever installed that subpanel was just trying to get paid. Did not do you any favors at all.

It would have added less than $20 to that job to give you a 20-space and a 70A feed, that you could’ve done something with. As it is, the panel is “maxed out”, even overloaded, with washer/dryer going at once.

I don’t understand why you have two washer/dryers. If that is a separate tenancy, there are a moose-pile of other issues that should be considered prior to any panel upgrade.

Since you’re game to add a panel...

Let’s upgrade the panel you already have. This is easy-peasy, since this is surface-mount stuff in unfinished areas of the home.

First, move that junk out of the mandatory 30x36” working space and it never returns. Now, I bet that panel is connected to the main panel through a short EMT “nipple”. That’s the way to do it, but you’ll want larger pipe - like 1” trade size (about 1-1/8” size if EMT) or even 1-1/2” if the holes are present and will line up.

So shut off that 40A breaker, pull the branch circuits entirely out of the existing panel and carefully tuck them out of the way. Undo that EMT nipple, un-fish the #8?#10? wires, and remove that panel from the wall.

Now get yourself a 30-space or 40-space main-lug panel. The breakers currently in your Eaton panel are $20 to replace, so you could go Eaton BR to preserve that “investment”. Other than that, I’m a big Siemens fan, both because they’re the same breakers in your main panel so you can just move them over... and because Siemens makes a dirt cheap generator interlock should you ever have the fancy. Make sure it comes with/buy accessory ground bars; can’t use neutral for ground in a subpanel.

Use a big conduit “nipple” between the panels (and if the holes line up, several additional little ones are always nice). Use metal as that automagically takes care of grounding.

Wire the new panel

With the new panel mounted, reconnect all the existing wires and cables exactly as before, and get your upstairs laundry room powered back up. Everything is the same except now you have 22/32 more spaces than you had before.

I created this as a “break point” - you are back up to full functionality (as was before) and under no time pressure to do what follows. Better, the old work is a template for how to do the new work.

Now, look at the 40A breaker and the #8? #10? Wire going over to the subpanel. Replace the 40A with a 100A or 125A breaker, but leave it turned off.

Now, one wire at a time, replace the 3 existing THHN/XHHW wires with

  • If 100A, #3 Cu or #1 Al wire, THHN or XHHW.
  • If 125A, #2 Cu or #0 Al.

These wires typically come black. Use tape to re-mark the neutral wire with white tape.

Once all wires are replaced, you can power up that breaker. Now we have plenty of room in the subpanel, both in spaces and amps, and can rearrange as needed.

Another natural breakpoint. From here on out, you can move circuits around one at a time.

If you have a mind to “generator” in the future, move circuits you’d want on generator to the new panel, but reserve the top 4 spaces for the generator interlock. Also leave enough slack in the #3-#0 cable that it can reach a branch circuit breaker in the top 2 spaces, instead of the lugs.

Now, about that kitchen...

From the data you clipped off the instruction manual, it basically says “See nameplate” which you didn’t show. But we can make an educated guess.

First, a PSA for running 1” conduit between panel and the kitchen range/oven area, as a gift to your future self / future other homeowner. This lets you run whatever the future needs will be, up to 3 circuits. Further, since wires are allowed to run hotter in conduit, you can get more ampacity from smaller wires - for instance #8 is good for 50A in conduit, so a #8 run handles any future range/oven.

Code requires at least about 7 circuits for a kitchen these days. I always laugh when people build ADUs (in-law apartments) and they fit a 12-space panel.

However, you’d be doing yourself and the chef a favor if you also

  • Put the refrigerator on a dedicated circuit, or at least one that is not GFCI protected. The goal here is to prevent both a) nuisance trips (fridges trip GFCIs rather quite a lot, and needlessly since they are well grounded and shielded)... and b) trips caused by other things, which would result in spoiled food. That can happen if the resetter is unaware that thing also powers the fridge.

  • Have more than the statutory minimum two kitchen countertop circuits, so the chef can run more than 2 heat appliances at once, and doesn’t have to guess which plugs are on which circuits. (Heat appliances, typically 1500W, hog the entire circuit).

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    @David wow, so he did not even use a conduit nipple? This guy is a professional Romex flinger who probably doesn’t even know what EMT is. You’re better than that... OK so you won’t be able to use the old THHN wires as a template. But you can still use them as a checkpoint, just go ahead and re-fit them as-is, and route the new wires in the nipple... – Harper - Reinstate Monica Jun 30 at 17:16
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    @David No no, the work isn’t improper, just oddly done. The electrician obviously has a very limited comfort zone, and can only think and work in a small subset of total electrical skills, i.e. Romex cable only. So did not exploit more efficient (and easier IMO) ways to do that thing. But the work was correctly executed. – Harper - Reinstate Monica Jun 30 at 17:36
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    Got ya. He did use the wrong sub-panel breaker tho. – David Jun 30 at 17:41
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    Yes, when panels are mounted like that, you simply use a very short EMT conduit (i.e. a nipple) from the left of the main panel to the right of the subpanel. Properly installed non-flexible metal conduit is an approved ground path. Use the biggest diameter that both knockouts will support. And feel free to add some more between 1/2” and 3/4” knockouts if they line up. No such thing as too many interconnects! Especially if you start moving circuits over. – Harper - Reinstate Monica Jul 1 at 5:12
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    @David yeah, your setup sounds great. And that balancing is, well, not something you even need to worry much about since you have a lot of ampacity. I mean if we get out the sharp pencil and look at provisioning, we're barely 50A for the two big loads even if they were run at once... and that leaves plenty of room for the 120V loads you mentioned. It's OK for miscellaneous 120V loads or even some 240s to oversubscribe a panel by 200% or more. Just don't do it with loads expected to be simultaneous or continuous, like racks of Bitcoin miners or matching EVSEs. – Harper - Reinstate Monica Jul 16 at 13:13
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I have a couple of ideas: First is the "get by". Second is "prep for the future".

The "get by" options: Get 2 15 amp tandem (double stuff) breakers, remove the 4 15 amp breakers next to each other (red box in your pic) and move the circuits to the new tandem breakers. That would free up 2 spots for your range circuit. You might also be able to combine a couple of lightly loaded circuits, but I don't recommend that.

The "prep for the future" option: Replace that small sub-panel with a much larger one and upsize the wiring and breaker to it. Sub-panels aren't that expensive and with such a short run from the main panel, wiring cost would be low as well. That's my recommended approach. A kitchen remodel is a decent sized project and adding a few hundred bucks to properly support it as well as other expansions is money well spent. You didn't say if you were planning on doing the work yourself or hiring an electrician, so that will affect the price of course.

The more I think about it as I write this I'm strongly recommending replacing the sub-panel and it's feed to something much larger.

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  • Thanks for the tandem breaker idea, George! Completely forgot about those. I don't think we will need any more new circuits but I will keep the sub-panel upgrade idea in-mind. I will likely be doing wiring to the panel myself but will bring in the licensed electrician to inspect and connect to the panel. Mainly to ensure proper load-balancing, especially with moving around 4 circuits with tandeb breakers. Do you think you can give me any input on the oven wiring/breakers itself based on installation requirements provided by the manufacturer? It was a bit confusing for me. – David Jun 30 at 14:37
  • Sure. When you get into the larger wire sizes they get costly, but from looking over your panel it would seem you have a nice large house built within the lat 15 years or so (sleuth-ed out by the areas required to be protected by AFCI breakers at the time!). So maybe cost isn't too big an issue. If so, I'd run 6/3 copper with ground for your new range. Technically you could run 8/3 bc the larger model only requires 40 amps even 10/3 for 30 amps for the smaller model range. You can always put a lower amp breaker on larger wire, but not the other way around! So if the run isn't too far, do 6/3. – George Anderson Jun 30 at 14:44
  • Some people here suggest aluminum wire to save money, but I really really don't like that stuff except for mains or distant sub-panel feed with substantial power requirements. It can save a lot of $$$ in those situations, but I'm mostly a copper guy!!! LOL – George Anderson Jun 30 at 14:46
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    @David Keep forgetting about double-stuff breakers. Between NEC 2014-20, they are all but outlawed. So many circuits require AFCI or GFCI-at-the-breaker that you can hardly use them anymore. Aluminum wire is fine for feeder, heck the subpanel lugs are aluminum. – Harper - Reinstate Monica Jun 30 at 15:49
  • @Harper-ReinstateMonica Why on Earth bother with AL wire, the noalox goop required, the stiffness of larger gauge AL wire for such a short run? Regarding the double stuffs, yeah, for new construction, but what about this specific case? Still, like I strongly recommended to the OP, replace that dinky sub-panel and prep for the future. – George Anderson Jun 30 at 15:55

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