Grounding from bus bar

[vespucci]

Hello.
I have 4 big bus bars. 2 positive and 2 negative.
Between the first ± and the second ± bars sits the main power switch.
The fist ± contains connections from Batteries, Chargers and what else needs constant power
also when the main switch is off.
To the second bars ± all loads are connected.
But these bars have not been grounded. So I installed a grounding plate
onto the hull of my boat. But how do I ground these 2 bars?
It is by purpose that also the negative is switched.
If I connect both negative bars to ground I will bridge them.
But I want to ground either Batteries as Loads?

 

[dingbat]

Pretty convoluted.....what exactly are you trying to do?

The negative terminal on the battery is your "earth" or "reference" ground. All grounds must be tired back to the negative battery terminal.

The use of multiple ground references (potentials) is just asking for problems.

 

[vespucci]

I saw that my last sentence may have lead to confusion. I wanted to write that I wanted to ground both bars, the batteries and the loads. Sorry!

I am just trying to ground my negative bus bar. And the two bars are disconnected when the main switch is off. So when I ground the first bar, the second is only grounded when the switch is on.

 

[alldodge]

Remove the switch between negative buss bars so its always ground

 

[vespucci]

Not a bad idea. But don't you think that the boatbuilders had an idea behind that, when they installed it?
Ed Sherman from Cruising World wrote the following about the subject:
Switched DC negative is typically a European electrical feature that you rarely if ever see on American built boats any more. In commercial applications where the hull material is steel or aluminum, we used to see this approach taken quite often. Furthermore, you may have actually seen double-pole circuit breakers for the DC branch circuits that would simultaneously open both the DC positive and negative conductors. The origin for all of this was a valid fear of stray electrical current causing rampant electrolytic (stray) current corrosion. By completely isolating the battery(s) a boat owner could pretty much be assured that without any power source, all chance of this happening were eliminated.

I realize, there is much more to read about this subject and will before making any further comments.

Thanks a lot @alldodge for the input!

 

[dingbat]

What problem are you trying to solve?
If your trying to do what I think you are this makes no sense

What kind of boat?
What kind of engine power?
Where is the bonding circuit connected in your diagram?

Suggest you read up on galvanic corrosion, bi-metallic coupling and bonding.

Big problems related with using multiple ground potentials in general