I just fixed a hard-to-find short circuit in my home wiring. I had heavy gauge aluminum wires running from two 40 amp circuit breakers to bring 220V to my electric cooktop. My guess is that those were the original wires from 40 years ago. Those wires were spliced to copper 10G wires in a junction box and then they ran to another junction box near the cooktop where they were spliced again. One of the aluminum /copper connectors melted in that middle box. This was very hard to diagnose.
Question: The cooktop label says 7KW for 120V/240V; 5.3KW for 120V/205V. Someone suggested that I should replace those 40A breakers with 30A breakers if the the appliance can run on the 30A as it would be safer. Can I just take 7000 divided by 240 = 29Amps? Will that be okay? Or do I have to take into account RMS voltage and current? I don’t remember whether these ratings are in peak to peak. I think my cheap meter shows peak to peak, not RMS.