The posted directions at the campgrounds we hooked our popup 30 amp system into said to first turn off the site circuit breaker, then plug in, then turn on the breaker. Sounds like they expect a load from the camper. We follow these directions and get no arc. Disconnecting directions are the same. Turning off every 120 volt circuit breaker in the camper should produce no arc if wiring is in good shape. Also, we travel with every 120 volt circuit breaker in the off position to reduce the the chances of parasitic current loss, especially the 12v/120v converter.