[JimLilly]

As an electrician all my life I was looking for a similar answer to your question. Have a couple of devices like my laptop charger and a digital projector that would have been a pain to convert to 12 volts. I looked at transfer switches and electrically held DPDT contactors but didn't feel like investing the time. Ended up plugging a good quality extension cord into my 1800 watt inverter which is mounted in the rear with my two 6 volt golf cart batteries. Plug the other end into a 120 volt adapter for the TrailManor cord. Easy Peasey. Totally eliminates any chance of being plugged into shore power while plugged into inverter power. Just need to be wary of running the other high amp draw TrailManor devices like the AC unit, but this would be true for any of the transfer switch solutions also. You could turn off the breakers for these devices if you felt so inclined. On most TMs turning off the breaker for the refrigerator / water heater (which you probably don't want to run on 120 volt from your converter anyways) will kill power to your converter. Sometimes the easiest solutions are the best.