I took my camper to my daughters house. Son in law said he wired in a 30 amp breaker. I asked if it was 120, he said yes. I plugged in, and no joy and progressive EMS wouldn't start up THANKFULLY. He had bought a double breaker (240) and wired that in. Once I fixed it, everything worked fine.
No doubt without the EMS, I would have fried a bunch of stuff in RV.
Mike