[Cyride]

A 50 amp RV outlet is a single phase 125/250 volt outlet with neutral and ground (four prong device). The 30 and 20 amp outlets are 3 wire 120 volt devices (no 250 volt). It is my understanding the load center in an RV is split and when operating on the 50 amp branch circuit it powers two separate 50 amp busses. When running on the 30 or 20 amp branch circuit half of the buss in the load center does not get power.

If you are plugged into the 30 or 20 amp outlet there has to be something that will not even power up (like maybe one or two of the A/C units).

I would assume if you were plugged into the 30 or 20 amp outlet the refrigerator would be on the buss that would supply power to it along with maybe an A/C unit and some lights.

That is why I was asking if the refrigerator would run on just a 120 volt circuit. It would have been more clear if I said "if plugged into a 20 or 30 amp outlet".