I was advised by someone who worked at the yard, that a Balmar regulator (atleast the type I have - Digital Duo Charge), needs to connect to the System Ground (where System Ground means sea-water) or it would be damaged. The diagram from Balmar website also indicates that a ground connection is needed: Digital Duo Charge | Balmar
When I bought the boat there already was a green wire that connected the ground bus to the thru-hull. My concern is the thru-hull was covered in green-stuff (which could just be oxidation) and was leaky. It looked like the leak was coming from a bad seal, and the thru-hull was fine except for oxidation, but it is hard to know for sure, since I had the thru-hull replaced and neglected to properly examine the thru-hull for corrosion, so I cannot know for sure if the thru-hull was corrosion damaged or simply the sealant gave way.
I found this on the Balmar website, and they clearly say that you need a "System Ground
" which means actual ground (on page 2 here: http://www.balmar.net/wp-content/upl...nual-REV.B.pdf
The Digital Duo Charge must be properly connected to system ground, which must be shared between the house and starting battery banks, for proper operation. Failure to do so will result in non-operation and potential damage to the device. Connection to system ground can be made at one of the following: house battery negative post, starting battery negative post, or system ground bus. User-supplied 14-gauge wire is recommended. To install the ground wire:1. Select a length of 14-gauge wire long enough to extend from the Ground Terminal on the Digital Duo Charge to your intended ground source, such as a ground bus as shown at right.2. Crimp appropriately-sized ring terminal and 1/4” female spade connector to the wire ends.3. Connect the female spade terminal to the Ground Terminal on the Digital Duo Charge.4. Connect the ring terminal to the desired ground source.
Here is a good resource I found on the difference between System Ground and equipment ground (which matches what the Balmar manual states above): https://electrical-engineering-porta...-ground-system
System grounding means the connection of earth ground to the neutral points of current carrying conductors such as the neutral point of a circuit, a transformer, rotating machinery, or a system, either solidly or with a current-limiting device.
I guess, my main question is is it safe for the ground to be connected to the thru-hull, or will that cause corrosion problems later on?
It seems pretty obvious to me that a System Ground is needed in the case of my balmar regulator.