With a factory instaled generator in your unit(camper). You are pluged into shorepower and the elect goes out! You go over and start the generator. Do all generator systems have automatic safegards to prevent backfeed of the electric to shorepower? youroo!!
You mean transfer switch?
There are several types of doing that depends of year and price.
In very old motorhome the generator had an outlet. In order to have the power from generator to the coach I had to plug the shore cord in it. There is no way to have one plug in 2 outlets at the same time. On other coach I have manual transfer switch. It is a special switch with stop on the center, so you can't switch from one source to the other without a delay.
Than in my inverter/charger automatic transfer switch will act so fast, that TV won't even blink.
Pessimist sees dark tunnel, optimist sees a light at the end, realist sees lights of coming train.Engineer sees 3 idiots on the tracks.