Whether the existing wire can be used depends on the insulation rating of the wire. There will be some lettering printed on the outside of the wire cable that will indicate this rating. If the proper rating is present, a 50 amp breaker can be used with it. If the proper rating is not present, the wiring will need to be replaced.

https://media.distributordatasolutions.com/ThomasAndBetts/v2/part2/files/File_7437_emAlbumalbumsOcal20(USA)oc_1_g_nec31016pdfClickHerea.pdf

@formulaross20 Will the wires in the electrical panel have the rating printed? I’m comfortable with opening up the panel and checking, but not going into the wall or in the crawlspace to check. This isn’t a question specifically to you, but I wonder why we had 3 unrelated contractors all recommend we only switch out the breaker? What would be their incentive since they’d actually make more on the project if estimates included electrical rewiring work? Maybe they are speaking on a more practical level and don’t think that we are likely to max out the circuit. I honestly have no idea why they and our electrician feel differently about what needs to be done. 🤷🏼‍♀️

I'm not an electrician but no, you can't put a 50amp breaker on a 8 gauge wire. The stove will draw too much power and over heat the cable. Potentially causing an electrical fire. And you'll probably void your warranty.

You're better off leaving it as a 40amp breaker and avoid using all the burners at the same time so the breaker doesn't trip.

6 gauge wire isn't expensive. I think mine was under $2/ft and it took 15 minutes to fish the cable through the walls/floors to the electrical panel.

I hope the GC you hired is licensed and insured...

Referring to the NEC chart above, Cherie is incorrect that 8 gauge wire cannot be used with a 50 amp breaker; it all depends on the temperature rating of the wire insulation.

The Frigidaire FPIC3677RF and FFIC3626TB ($848 at Home Depot) 36" induction cooktops only require 40 amp circuits.

Another thing to check for the specific cooktop you intend to buy is if the 50 amp rating is recommended or REQUIRED. In the case of my Electrolux induction stove with double ovens the recommended amp rating in USA/Canada, where I live, is 50 but the minimum required is 40 amps. 10 years of use on 40 amps no problems. The way induction is configured on most home cooktops and stoves all burners cannot be on boost at the same time hence the maximum rated amp draw will never be reached. If this recommmended/required difference applies to your cooktop and the 40 amp is the minimum then no need for going in the crawlspace to check wire insulation temp rating or breaker change. Easy for everyone.

Is this effort permitted?