You are talking 2 different power sources in your Class C (almost all RV's) one is 12 volt runs all lights, water pump,heater, hot water heater, refrig. , The other is 110 volts runs elec. outlets,microwave, A/C unit , hot water heater if you have a heating element, refrigerator when not on propane.
So the next question is are you blowing 12 volt fuses, or 110 breakers,
You may have an inverter (takes 12 volt and makes 110 volts) but I don't think you do. More then likely you have a converter (takes 110 volts and makes 12 volts) and also charges your house battery when connected to 110 volts.
On some units the fuse panel has the converter in a metal enclosure under the fuses (12volt)
When plugged into 110 volt take a reading at the pos. house batt. post if the converter is working you should be getting close to or over 13 volts to the battery which shows the converter is working and charging the house battery. If not the converter is not working or not getting power.