Thanks in advance as always for any expert advice. Oday 26. I sail on weekends for up to 4 days at a time. I'm going into a known "hot" marina. My setup is: One deep-cycle battery hooked up to a flexible solar charger. I have one bronze thru-hull on the bottom of my boat, and I pull my outboard up and out of the water when my boat is tied up. I connect to shore power with an all-weather contractor's cord with an in-line GFCI and 30amp adaptor to occasionally run a heater in my cabin when it's cold, and to top up my battery through a Guest 3-phase charger. I do not have a standard yellow 30amp connection on my boat. I do plan to eventually get 30amp wired on my boat, but until that time, do I need a galvanic isolator in my situation?
Do I need a galvanic isolator?
- Thread starter AircooledPatriot
- Start date
- Status
galvanic isolator
It is probaby a wise investment as long as you typically are connected to shore power but since your prop isn't in the water at the dock, the q arises - what are you trying to protect?. Testing to see if stray current is present is more complicated than simply dropping a lead from a multimeter in the water or checking voltage across the shore power ground. If you really want to do so, ask and we can provide some advice. An isolator or transformer is usually needed only when the boat is routinely connected to shore power and the running gear is always submerged.
It is probaby a wise investment as long as you typically are connected to shore power but since your prop isn't in the water at the dock, the q arises - what are you trying to protect?. Testing to see if stray current is present is more complicated than simply dropping a lead from a multimeter in the water or checking voltage across the shore power ground. If you really want to do so, ask and we can provide some advice. An isolator or transformer is usually needed only when the boat is routinely connected to shore power and the running gear is always submerged.
Thanks so far...
Don, thank you for your response. I'm no electrical guru when it comes to boats and the running gear is what I've read up on as well. This is why I stated my outboard will be out of the water and the only metal things in the water is my keel and bronze thru-hull. I'm not sure if I'm going to become a battery conductor with my setup. Ed, while installing a Marelon a few days ago, the thing snapped, so I went back to bronze. That hole in the bottom of my boat is very important to my family's safety so I went with the sturdiness of bronze after trying the Marelon.
Don, thank you for your response. I'm no electrical guru when it comes to boats and the running gear is what I've read up on as well. This is why I stated my outboard will be out of the water and the only metal things in the water is my keel and bronze thru-hull. I'm not sure if I'm going to become a battery conductor with my setup. Ed, while installing a Marelon a few days ago, the thing snapped, so I went back to bronze. That hole in the bottom of my boat is very important to my family's safety so I went with the sturdiness of bronze after trying the Marelon.
Don't need one
You "might" need on if your thru-hull is bonded electricly to the boat ground. Most are not. So as long as your thru-hull doesn't have a bonding wire and the hose that connects it to the boat is non-conductive you are set.
You "might" need on if your thru-hull is bonded electricly to the boat ground. Most are not. So as long as your thru-hull doesn't have a bonding wire and the hose that connects it to the boat is non-conductive you are set.
No, but check your wiring and your zincs
Use a multi meter and measure the resistance between the AC ground and the battery charger leads, with the charger unplugged. Battery chargers have transformers in them and can be galvanic isolators. The metal case should be connected to the AC ground, for safety reasons. If the battery charger leads are isolated from AC ground and the case is not connected to any boat ground, you have galvanic isolation (sort of). Some boats with inboard engines have all the chainplates and thru-hulls electrically connected to the engine and prop. A zinc is needed to preserve the prop and thru-hulls. It gets attacked by electrolysis instead of the thru-hulls. Thru-hulls that are not connected to a piece of steel or stainless that is also under water will last a lot longer, but because of the humidity they will not be completely isolated. Your only guarantee that they won't be attacked by electrolysis is to have them all connected to a zinc.
Use a multi meter and measure the resistance between the AC ground and the battery charger leads, with the charger unplugged. Battery chargers have transformers in them and can be galvanic isolators. The metal case should be connected to the AC ground, for safety reasons. If the battery charger leads are isolated from AC ground and the case is not connected to any boat ground, you have galvanic isolation (sort of). Some boats with inboard engines have all the chainplates and thru-hulls electrically connected to the engine and prop. A zinc is needed to preserve the prop and thru-hulls. It gets attacked by electrolysis instead of the thru-hulls. Thru-hulls that are not connected to a piece of steel or stainless that is also under water will last a lot longer, but because of the humidity they will not be completely isolated. Your only guarantee that they won't be attacked by electrolysis is to have them all connected to a zinc.
- Status