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Blew a 40 amp fuse three times before figuring out the trick | Dredge Operators - SMM Buzz

Blew a 40 amp fuse three times before figuring out the trick

Kept tripping on my bucket ladder circuit. Third time I finally checked the cable twist instead of swapping parts. Turns out a kinked shore cable was pulling more amps than usual. Anyone else deal with underwater cable snags causing phantom draws?

3 comments

3 Comments

kimr103mo ago

Same thing happened to me on my old 30 foot sailing yacht... the shore cable got pinched under the dock from the tide moving it around and it started pulling way more amps than it should have. Took me blowing two 50 amp fuses before I realized it wasn't the charger at all but just that cable getting squished.

dixon.spencer3mo ago

Yeah I had a similar issue on my Catalina 27. The dock cable got pinched under a floating dock section during a spring tide. It was pulling like 35 amps on a 30 amp breaker but the breaker never tripped because it wasn't a dead short, just a slow meltdown. I found it by touching the cable near the plug end and it was hot enough to burn my hand. Now I always take a spare cable and a pair of those leather gloves with me. Also check your galvanic isolator if you have one, that kind of damage can fry it too and then you start getting stray current corrosion on your thru-hulls.

allen.ivan3mo ago

Use a rubber gasket or a split loom tube where the cable goes over the dock edge. I saw a guy lose his whole shore power setup last summer because the insulation got chewed through by the dock cleat after a storm. Once that copper touches the dock frame or the water you are basically shorting out your whole system. Another thing is check the plug end too, they get hot and melt the plastic inside if the connection is loose. I started carrying a spare cable and a clamp meter after that happened to me. You can catch a bad draw just by feeling the cable for heat before it blows anything.