cathodic protection.

[Skiffing]

Check the polarity too. That's easy to check and easy to mess up on. If the cross is somewhere in the house before the docks lights branch out the electrician may not have even checked it - or cared.

There's an easy way to check potential across common / ground to earth [the water at the dock] but I can't remember for sure how to do it.

 

[PSG-1]

Thanks for the info! I think there's a tester you can plug in to a receptacle to tell whether polarity has been reversed.
My anodes will be here tomorrow, so I can go ahead and get the galvanic protection back on the boat.