Jill, if your trailer has a microwave oven, the trailer may be wired so that a hidden switch enables you to use either the microwave, or the A/C, but not both at the same time. The 30 amp supply is not sufficient to run both simultaneously. In our trailer, the switch is in the locker above the stove, and it is labelled for microwave in one direction, and A/C in the other switch direction.
Nick Crowhurst, Excella 25 1988, Dodge Ram 2500 Cummins Diesel. England in summer, USA in winter.
"The price of freedom is eternal maintenance."