I'm converting a toy hauler (a big enclosed trailer) into a *******'s RV. I'd like to install a small water heater, an electric range, and a refrigerator. The three appliances together would peak at over 30 amps, but each of them separately would consume under 15 amps. I intend on using a regular household outlet to get power to the trailer. Most outlets are rated at 15 amps, and regular extension cords are rated at this amperage too. So I need some kind of way keeping all the appliances from turning on at once and of prioritizing which appliance gets the power. The stove would get first priority, then the fridge, then the water heater. I need a relay that's able to disconnect two of the three circuits whenever one is in use, while respecting an order of priority. Does anyone know if this exists? I know motor homes use an "Energy Management System," but I have been unable to find one, and I suspect they cost too much anyway.