Im 99.9 percent sure I have this right, but I want to confirm. During surgery I paid a licensed electrical guy to run a sub panel. I found he did it wrong and not by code placing it under the kitchen island. So I decided to use the already run 90 amp 2/0 aluminum wire and put in a box to power the 40 amp cooktop. Now I did use an approved al/cu connector in the box. I do of course have dual 40 amp breaker on panel box. I have a repair guy coming out and while I feel this is adequate, I wonder if he will try to fault this to the problems in the cooktop.