Yes, it is safe to leave shore power connected all the time. Most people only disconnect shore power when they get underway. That way, the fridge stays cold and the batteries stay charged.
@cschnetz now I understand your question and as @LaRea said, normal to do so. In fact depending on how you are setup if you turn batteries off your 12v systems may not work as this way isolate the charger feed too.
Answers
Regards,
Ian
The Third “B”
Secretary, Ravena Coeymans Yacht Club
https://www.rcyachtclub.com/
Regards,
Ian
The Third “B”
Secretary, Ravena Coeymans Yacht Club
https://www.rcyachtclub.com/