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House has a 50A, 3-line service to the old Range.

Want to instead have a separate Cooktop and an insert Oven located below it for a sleeker more integrated look. Each have a 30A requirement.

Can they both connect to the 50A feeder?

We have no good way to replace it with 2 separate circuits without replacing the whole electrical panel, and massive damage to ceilings, etc. to get it there.

Is it possible to share?

A range would have just as many burners and an oven on that same circuit, so it seems plausible. Could replace the 30A cords on the appliance with 50A? Or is it possible to fuse the 30A appliance cords in the J-Box before connecting to 50A home run? (We'd need the J-box concealed in the cabinet, so a sub-panel option wouldn't work.)

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    Welcome to Home Improvement. At a minimum, a clear, focused picture of your breaker panel would help - the electricians here are quite good at coming up with possibilities that may not have occurred to you, but they need to at least see what they've got to work with.
    – FreeMan
    Feb 9 at 11:42
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    Can you post photos of the inside of the range's junction box? Is replacing the existing cable run or running a cable back to the panel by another route in the cards? Feb 9 at 12:41
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    Do you know if this is "3 wires and that's it" - which means hot/hot/neutral+ground-together - or if it is "3 wires plus either a separate bare-so-don't-count-it-the-same or metal-conduit-which-handles-ground"? That makes a big difference. If you're not sure, pictures of junction boxes would help. Feb 9 at 14:57
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    @ThreePhaseEel no, not really since a subpanel needs the access and clearances. Wall of cabinets, prominent to the kitchen/living area, with nowhere to put anything we can't hide inside a cabinet. Wires are all insulated. White, Black and Red. All stranded, but I haven't determined the exact size yet. In discussion below, I suggested adding a ground out of the wall to a rod to bring it up to standards since getting a ground back to the panel is a problem. What do you think of that?
    – Blobfish
    Feb 10 at 3:46
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    @Blobfish -- a rod does you not a whit of good here. HOWEVER: can you find a path back to the wire that connects your panel to your water pipe and/or ground rods, and is sacrificing a little-used cabinet near the range an option, for that matter? Feb 10 at 4:29
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Actually with no structural changes it may be a redecorating project. In several states that I have lived many people doing cosmetic updates like your project do not know the proper terms.

With the wrong term they end up doing way more than what is required.

for example in my current state if the receptacle is not moved more than 6’ the original wiring is allowed (we are on the 17 code with state exceptions until April). In this case if the wiring is properly sized a large junction box being tapped for both devices MAY be acceptable is the box accessible after the work is complete? it all goes back to the AHJ so the location would be needed to know for sure but when the home was built the tap that you want was acceptable see NEC 210.19.3 and for a picture see exhibit 210.24. Last if tapped from the junction box to the next device usually requires conduit.

I do agree with most of Retired master electricians answer but the jurisdiction here is a big deal and I would not be pulling a new feeder if I could be in compliance with my state requirements. If you happened to have 3 insulated conductors (unlikely but possible) pulling a single ground wire I would do to bring up to the current code.

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    Notwithstanding the issues of the neutral, NEC otherwise allows oven+cooktop to share a circuit, and it's common enough that people replace a range with a cooktop+oven combination. 220.55 has the table - for two appliances at 30A (7.2kW each) it falls in column 2 (3.5-8kW) allowing a demand derate of 65% for a total (derated) demand of 9.4kW (less than the 11kW max derate demand), so I think this is fine.
    – J...
    Feb 9 at 18:38
  • Thank you both! Very very helpful. Would it be ok, or better at least, if I add a ground wire straight out to a new ground rod? I don't have any good way to get a new wire back to the panel.
    – Blobfish
    Feb 9 at 19:50
  • @j... I agree yes we can derate. However a few years back a restaurant was wired to code the minimum allowed. It was rebuilt again to the minimum allowed code and it burned down again. The insurance did not want to pay again but needed up on the hook. I like to know the actual wattages and uses planned usage before going whole hog with the derate (they always want to add or a piece of equipment comes in a kw higher than estimated. Leaving some wiggle room is usually a good idea but yes we can derate.+
    – Ed Beal
    Feb 9 at 19:50
  • Blobfish I did not see what you have. A hot hot neutral all insulated then yes it is appropriate to take a ground back to the rod if it is closer or easier to get to than the panel. This is a new allowed method of adding a ground. If your existing conductor is not insulated it really won’t help. If any answers or comments are helpful upvote or accept that helps others find them.
    – Ed Beal
    Feb 9 at 19:54
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    @j,,, you haven’t seen my wife’s final kitchen plan. LOL we had to convert to gas or bump the service to 400a.
    – Ed Beal
    Feb 9 at 19:58
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There are 2 parts to your question.

First you can run a 50A circuit to the kitchen and tap the circuit and run one tap to the cooktop and one tap to the oven. So long as both tap conductors are over 20A and the circuit cannot exceed a 50A supply. I found this in the 2020 NEC Handbook (A)(3) Exception #1.

The real problem is you feeder is a 3 wire which means it shares the neutral and ground conductor and this is no longer allowed. Since this is a remodel you must bring the feeders to all equipment up to the newest code. You can reuse the 50A 2Pole breaker for the range feeder but you must replace the old cable with a new #6-4 wire feeder (2 hots, 1 neutral, and 1 ground).

If you feel you need more clarification. I would advise you to check with you local inspector (AHJ) and see what they have to say.

Hope this helps and good luck.

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    Keep in mind that we have not established that OP understands what "3-wire" means or that they have used the term correctly in their question.
    – J...
    Feb 9 at 18:12
  • Thank you. I do understand the 3-wire vs 4-wire. As explained above in a comment, any wires run back to the panel would have to be exposed - nowhere to hide in a post-& beam home - so I ask the following possible solution: Can I run a ground out the wall to a ground rod instead of back to the panel?
    – Blobfish
    Feb 9 at 19:41

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