Aluminum wiring question
 

As it turns out, my house is wired with aluminum (bummer). I want to run a new circuit to my cooktop using copper wire.

Question: Can I install a circuit breaker into the existing box and wire my cooktop with copper ?

Yes, but the AL is fine for this either way.

Don't you have another thread on this topic already? http://www.houserepairtalk.com/f9/wiring-cooktop-help-8343/

Yeah, the more copper the better. There are rules about connecting copper to aluminum but that should not be an issue since you are running a new circuit.