First, GFCI should protect the circuit from leaking electricity in the water. My story, all of our docks on the lake are over 20 years old. Most were not wired by electricians. I had my underground line to my dock cut by the sprinkler guys when they expanded my system. It was near the dock so I took the opportunity to set a post and a GFCI plug at the splice to protect downstream circuits. As soon as I turned it on it snapped. My old boathouse was wired with plain old white ROMEX and it had sagged into the water several places. Even though it worked and didn't trip the breaker it was leaking electricity in the water.

Experts now believe as many as 90% of drownings near docks are actually electrocutions. I got a new rule passed by our association that all docks had to be protected by shoreside GFCI or be disconnected from shore power. I ended up replacing all the wiring in my boathouse with underground feeder armored cable to get it to quit tripping the GFCI. I also wired it well above the waterline, although it can trip in a flood.

Ross Canant