There are options to add a second A/C without having to upgrade existing Airstreams to 50amp/240v service.
One option is to add a dedicated 120v line, with single circuit breaker, for the AC.
That dedicated line could be a standard extension cord plugged into the 20amp outlet on the campground power box:
Or the dedicated line could be pluged into one half of a 50amp/220v spltter like this. The Airstream's maim power umbilical plugged into the other side. Each side could supply up to 50 amps at 120v when fed by the 50amp 240v campground outlet.
is to leave everything as-is and let the second A/C unit share the oven/microwave circuit with a smart power sharing gadget. It connects two high current appliances to one breaker even though together they would trip it.
It is called a priority switch, load shedder, or automatic energy select switch
It works by hooking two high current loads (up to 20 amps each) to the black box and then running the input to the breaker.
So.... the existing microwave breaker would only have capacity to serve the oven or
the second A/C but not at the same times. But consider that it would be OK to pause the A/C for a minute or two while the microwave runs.
Place this automatic switch near your breaker panel and hook wire going to the microwave to high priority side of it. Hook the second A/C unit to the low priority side.
- If you turn on the second A/C when the microwave is off, it works.
- If you turn on the microwave when the second A/C is off, it works.
- If you turn the microwave on while the second A/C is running, power is paused to the A/C until the microwave is finished.
- If you turn the second A/C on when the microwave is running, it will wait until the microwave is finished and then the second A/C goes on