I'm planning on buying a 30" MMW9730A Maytag oven microwave combo. The install instructions seem generic about the amperage and wiring stating it's a 240vac 5520w at 30.5amps. Currently I have a 3 wire (with a 4th ground) 10g wire going to 2 phase 30amp breakers. If my math is correct 5520w shouldn't be pulling more than 24amps which would fall in the %80 range. So why do they state it's pulling 30.5 amps? I've currently have the walls out and wondering if I need to spend the money to get this upgraded to 8g/40amp breakers or will the current wiring work?