I need to upgrade a 40amp to a 50amp. This 40amp supplies power to a sub panel that already has a 50amp breaker on it. How do I know if I need to change the wiring for the 40amp or if I can just change the breaker head itself and be done? It sounds like I need a 6 gauge wire but I’m not sure if the main panel is using 8 gauge.
Why would an electrician use a 40amp from the main panel to a 50 amp on the sub panel? Does that mean they possibly already have a 6 gauge behind the walls?