Winnebago also tends to design their electric systems with the converter and fridge on one breaker. Its a matter of two very compatible loads. If both are running, they will not overload the circuit.
On a 30 amp panel, you are limited by National Electric Code Article 551-42 (C)
This is quoting from the 2011 edition but this particular section has not appreciably changed.
(C) Two to Five 15- or 20-Ampere Circuits. A maximum of five 15- or 20-ampere circuits to supply lights, receptacle outlets, and fixed appliances shall be permitted. Such recreational vehicles shall be permitted to be equipped with distribution panelboards rated 120 volts maximum or 120/240 volts maximum and listed for 30-ampere application supplied by the appropriate power-supply assemblies. Not more than two 120-volt thermostatically controlled appliances (e.g., air conditioner and water heater) shall be installed in such systems unless appliance isolation switching, energy management systems, or similar methods are used.
This same section also requires energy management such as a load shed box, if you have three appliances controlled by automatic thermostats, such as a electric water heater, Air Conditioner, convection microwave, electric heating element for the absorption fridge.
This is a requirement because the manufacturer has chosen to comply with it, in order to maintain approval of the RVIA (that oval sticker on the outside of your RV). Some campgrounds, insurance companies, other organizations may consider it a requirement to get insurance, camp, etc. This is of course a way of excluding schoolies, ambulance conversions, van conversions, etc.
NEC doesn't say this for the fun of it, they specify such things as a way of providing a level of safety in the design of the system.
My SOB trailer had the electric water heater on a general purpose circuit, the microwave on a dedicated circuit, and the air conditioner on a dedicated circuit. On later models the manufacturer elected to install a manual change over switch and put the microwave and water heater on the same breaker. Great until you select MW and later turn on the WH and forget that it doesn't have any 120v going to it, and you are ready for a shower. I elected to install a load shed box that makes the WH and MW to both have power but when the MW exerts a load beyond the digital controls and the interior light, it shuts off the WH. When the MW shuts off, plus 30 seconds, the power to the WH is restored.
Charles
