Wiring upgrade case study

[DanielI]

I’m in the midst of installing new solar and instruments on my Catalina, and I’m finding a bunch of things I’m concerned about. Rather than posting a bunch of threads, I though it might me helpful to others if I documented my progress if some knowledgeable folks are willing to weigh in. I have read through Nigel Calder, and I’m generally knowledgeable about electrical circuits, but I have no experience with marine systems.

Let me start with a general picture of my panel and batteries. As you can see, the wiring is not terribly rats-nesty, but it could be better. Some concerns I have (as in, things I’m assuming need fixing) to begin with are:

1. There are no fuses on wires coming off the batteries, just on the panel.
2. It seems the DC negative is grounded to the AC ground. At least, I see continuity between my DC negatives and the black wires on the bottom of the panel, which are part of the AC. There is a big bus with green and white wires you can see behind the panel, but I can’t figure out where it connects.
3. The AC also not physically isolated, i.e., I can get to the wires without a screwdriver. FWIW, the AC is not a priority, as I do not currently use it (no inverter, no access to shore power).

A final comment: I’ve seen some similar threads in the past responded to with either, “get a book,” or “you can’t learn this stuff on a forum.” I’m happy with additional book suggestions (I’d appreciate comments on Boatowners Electrical Handbook by Wing or Replacing Your Boats Electrical System by Westin), but you can’t learn everything from books. Some things you learn by the questions that come up when doing, so I hope some of the experts here are willing to help out, and that maybe this will be useful to others, too.

Thanks in advance.