What is this Buss for? Grady provides the answer

[Dolce Vita]

i don't know if you ran it down yet, but i just took delivery of a new boat and the dealer pointed out an out of the way breaker and said it was for the ACR. i haven't spent any time looking in to it, but maybe you have the same thing. i know my 2009 did not have an ACR. good luck, ron

Turned out to be a redundant charging system original from the factory. I posted the schematic and response from Grady

 

[Dolce Vita]

Keeping it simple... with it in the Off position, what doesn't work?

FYI, that's a resettable breaker.

Also... check your wiring diagrams.

Dennis you were right it was on the original wire diagrams. I checked all systems and found everything to be in good working order. So I contacted Grady and the engineer responded with a redundant charging source from port engine for bank 1 our house battery. (isolator)

 

[Dolce Vita]

Assuming that he bought the boat new, the breaker has already been in the off position for four years, so if he hasn't noticed something not working by now, I don't think that is going to work.

I have just taken delivery of the boat in May 2021 as a used boat purchase. I was digging around under all hatches when I found it. And everything that I could test was working. Grady did provide the answer. See above for their diagram

 

[Fishtales]

better question is why is it needed and why no ability to monitor?