I think it's just going to be that you are possibly overloading the circuit capacity.
If you are on a 30 amp power supply, this is extremely easy to do. You have to be selective on what you can have on (and thus what has to be turned off) at the same time to keep from overloading the circuit. Those with 30 amp RV's have to learn energy management.
This link may help:
Basic RV Electricity - RV Information (RV Maintenance)
The easy way to see, is to add up all the amps of the stuff you are running (or if you know the watts, you can convert it to amps)
watts = volts X amps....or you can take watts/volts= amps. Say you're ceramic heater is running on 1500 watts, then you take the 1500, divide it by 120 volts and that gives you 12.5 amps.
Once you add up all the appliances, you may see you are over the circuit capacity. Many of the things will have a tag/baseplate that tells you the amps it uses.
Some often forgotten things that also consume 120 volt amps, are the fridge if you are running it on electric, and also the water heater, if running on electric instead of propane. When the electric heating element comes on in the water heater, it uses 1440 watts, or 12 amps right there.
Also, you have a converter that converts 120 volts AC to 12 volt DC, in order to provide power to your lights, fans, thermostats, CO detectors etc. The converters amp usage fluctuates depending on how many 12 volt items it has to power, thus converting more 120 volt to 12 volt. The more 12 volt stuff you are using, also is using more amps from the converter.
One more function of the converter is that it recharges your battery. If you have a bad battery, then depending on the type of converter you have, it may be trying to use a lot of converted 120 volt power to recharge it, thus using more AC amperage also.
The more times you trip a circuit breaker from overloading the circuit, it get's progressively weaker, and will trip easier (less amps) as time goes on.
I would advise to add it all up, and try to stay under your 30 amps (if this is what you have as a main breaker). It would be best to stay actually around the 25 amp mark if you are running the electric heaters constantly.
Hope you get it figured out.