Shore Power Question -- (15A+30A=45A)

Your RV is not your sticks and bricks home with a 200 amp service. Breakers are limiting devices for safety reasons. Can you draw more than 30 amps in a 30 amp rated coach? yes, for a little while until that breakker trips because of over heating. Your home and your trailer both have 110/120 volts entering them when plugged in. A 50 amp coach still has 110/120 volts entering the box. The difference is the distribution legs in the box each have 110/120 to them where the 30 mp coach has 110/120 powering both sides. Don't try fancy power gymnastics to "get more power". Manage your usage when you're a plugged into a 30 amp circuit. I never have any issues when my 50 amp coach is plugged into 30 amp shore power. You just have to understand you are limited in using the high wattage appliances at the same time.