The marina has some sort of electrical issue. It is over-voltage and under-voltage a lot. Seems a bad neutral wire. I have had a radio power adapter and a drill/driver battery charger go bad on me (plugged in at the work bench) so I am avoiding shore power for the boat.
Another boater suggested that the problem has ‘gone to sleep’ so I tried the shore power this afternoon. Unfortunately; same problem. There also seems to be some voltage in the water.
I know that I get a faint (usually faint) Reverse Polarity Indicator (RPI) at times so I decided to see if this is related. I did some experimenting (switching distro breakers off… comparing the generator with actual shore power… etc) and some reading online. I am pretty certain that the RPI is not related to the fluctuating voltage on the shore power. In fact; I think the RPI is coming on because there is a good draw on the AC (ie when charge kicking in or when I turn up the space heater) and this is causing a modest differential. This may be exasperated by some impedance on a connection on some high amp stuff (which appears to be properly installed). The RPI does not come on at all if there is no draw (ie charger and inverter is turned off). So I am going to ignore the RPI in some cases – as in the current case. I will pay more attention to it if it starts be a *bright* red light.