Stop me before I electrocute myself. Looking for neg ground

[randyp]

10 years ago I installed a house bank on the F26 using 2 group 29s wired in parallel, and a 20 amp battery charger direct wired to the AC and to the house bank and the engine battery for the single 318 on the F-26. The engine battery negative is wired to the common ground that's pretty much impossible to get to since it's on the port stringer under the engine. So, I grounded the neg house bank to the engine manifold and did the same for the charger negative. All the postives are fused and supplied with proper cabling.

The new battery charger has a neg lead off the DC output side AND a chassis ground, both of which are supposed to go to the negative ground buss, as I'm sure should be used for the house bank battery negative also. Should I be looking for another ground source for these leads (including trying to find a way to bond to the common ground under the engine), or is my approach still ok - grounding directly on to the manifold.

The present setup hasn't caused any problems and since I'm in fresh water I don't worry about galvanic issues.

Any and all advice would be appreciated.

Thanks!

[prowlersfish]

What you have been doing should be fine . What charger did you install ?

[randyp]

I'm installing the ProMariner ProNautic 1230P charger (30 amp). Seems to have the right amount of bells and whistles to make me think all the work I'm going through (EVERYTHING on the F26 is in an out-of-the-way place) will be worth it. Just wanna make sure I don't randomly fry something that I shouldn't. The wiring diagram with the charger shows all the negs going to the "Main Grounding Bus to Engine Negative". My F26 wiring diagrams show a "Typical Bonding System" with the negative ground being a bare wire that runs along the top of the port stringer under the engine. If I could get at the damned thing I probably tie it in there, but since it's grounding the engine it seems any big ole hunka cast iron, like the manifold, would also work.

Yah think????

[aweimer]

Yes you should be fine. The engine is bonded to that common on your stringer, and if you cannot get to it directly, bonding to the engine would be just as good.

[randyp]

Thanks. Going the manifold route will save a lot of time and back muscles.

[Big D]

...The present setup hasn't caused any problems and since I'm in fresh water I don't worry about galvanic issues...

So here`s my take on this, and again, there is more than one school of thought but I have found this to be the safest: though indeed the engine block and the ship`s ground (not talking negative ground) are tied together electrically at some point, it is safer to keep the AC chassis grounds separate from DC directly grounded hardware like the block. In other words don`t use the block as an AC grounding point. Instead, ground the AC component chassis directly to ship`s ground. Look at it this way; the engine block has one wire tying it to the ship`s ground, hard to get at by your own admission so probably not something you see every day or are aware of its condition. Now let`s say that you tie five AC component chassis to the block. All fine and dandy until the one wire that protects you from being electricuted (engine to ship`s ground) fails. Now suddenly, you have five chassis on board at full AC potential instead of just one when one of those chassis becomes live due to an internal short. If they were all tied directly to ship`s ground instead of the block, there would be no potential between the chassis and ground so if you touched a shorted chassis and other AC or DC grounded device at the same time (charger and engine for example), you`d be safe since electricity takes the path of least resistance (wire to ship`s ground) rather than through you. Hope this makes sence.


And by the way, being in fresh water does not protect you from galvanic corrosion., in fact stray current travels easier in fresh and brackish water, hense the need for mag and aluminum anodes rather than zinc.

[jefflaw35]

that makes alot of sence considering what I have taken out of my boat! all fried!

[randyp]

Thanks for the advice, Big D. I'm going up to the boat (still in the barn) this weekend and will try that approach, if possible. Could also track down the ships ground wire and run a lead off it, if I can get at it.