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Someone I know is working on a kitchen remodel in a condo in California and is (unrelated to the current round of discourse besieging the nation) enthusiastic about switching from a gas range to an induction coooktop. The catch is that they currently have a full panel and are limited to a 125A feeder (assuming the "125 AMP MAIN BRKR" labeling is accurate). What I'm wondering is whether they have enough room within the 125A service and the panel to squeeze in an induction cooktop.

Photos of the condo's subpanel and the original load calculations (from the building's construction, taped to the inside of the panel door) are below. Since those load calculations were done, LED recessed lighting was added, which is why a number of the breakers have been moved around. If they got the induction cooktop, the current 20A breaker labeled "stove" would no longer be needed for the gas range, which frees up a little space. Let me know if you need to see the inside of the panel, and I can try to arrange a photo of that or provide other necessary information.

If this is potentially feasible, they'd definitely get an electrician in to look at it further, but I was hoping for a gut-check on whether it's even remotely possible to accommodate an induction cooktop here within the limits of the 125A feeder.

Electrical service panel load calculations

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    What are the power requirements for the induction cooktop being considered? Full panel can be worked around with double breakers (2 half-width breakers in a 1-breaker-sized case), especially if you've made efficiency changes that reduce the load.
    – keshlam
    Jan 16, 2023 at 4:07
  • How many square feet is the condo in question? Jan 16, 2023 at 5:58
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    @ThreePhaseEel Thanks! Approximately 1,800 sqft. Jan 16, 2023 at 6:09
  • @keshlam I don't think they have a particular induction cooktop in mind at this point since they had been led to believe it would be impossible with this panel. Looking at likely models, I suspect it could be 30A, 208V/240V, but it would be useful for planning purposes to know whether there's room to go beyond 30A, as some models require 40A or 50A. Jan 16, 2023 at 6:13
  • Holy cow! They actually provided the original load calc right there in the panel? That's awesome! Have any other appliances been changed since this was done? Have any other significant loads been added?
    – FreeMan
    Jan 16, 2023 at 16:30

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There's room, but barely

Assuming that the stated loads for HVAC (2.1kVA * 2), the dryer (2.8kVA), the bath fans (300VA), and the fixed kitchen loads (5.1kVA) are all correct, said condo (sans oven, due to the way 220.55 works for now) is pulling just over 17.8kVA of load, or 86A @ 208VAC, as the condo in question has a "2 out of 3 phase" supply instead of a 240VAC split-phase supply. This leaves enough room for a circuit upgrade that puts the cooktop and oven on the same 40A circuit, which would permit a 9kW @ 208VAC cooktop to be installed alongside the existing 2.8kW @ 208VAC oven thanks to the Table 220.55 Note 4 provisions that let a separate cooktop and oven on the same branch circuit be treated as a single range load

Note that with a separate circuit for the cooktop, you're now working from a basis of 20.6kVA of load or 99.1A @ 208VAC since the oven's now included in this base number. This leaves you with only enough room for a 25A cooktop circuit, or a mere 5.2kW of cooktop @ 208VAC.

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  • Thank you! I have no reason to distrust the stated loads (none of those appliances have been replaced; the only significant change is the addition of the recessed LED lighting). One additional catch I hate to mention: they were also looking at also replacing the existing electric oven with this model, which is listed at 6,400W and says it requires a 30A breaker. Jan 17, 2023 at 0:37
  • Showing my ignorance here, based on the math here, it seems like those two loads together would be 6,400W (oven) + 7,200W (cooktop)=13.6kW, which would be too much for a 40A circuit @ 208VAC, is that right? But it could potentially work with a different oven? Jan 17, 2023 at 0:38
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    @ZachLipton -- a 6.4kW oven would leave them with a 5.6 to perhaps 6.0?kW budget for the range to avoid exceeding the current available at 208VAC Jan 17, 2023 at 1:36

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