I had been thinking about this thread and thought I'd try and find a couple of pictures and seemingly knowledgable guidance that is available on line. This is what I found last night on wiring:
http://marinesurvey.com/yacht/ElectricalSystems_DC.htm
Let me also say, this is the same website that I got the rather thorough discussion of fuel tanks: materials and installation proceedures that I have passed onto the forum a number of times. It may not be the final word in all cases, but the author appears to provide enough basic information and suggestions to get us started in the right direction on many topics. I suggest bookmarking the site in general and some of those sections you find particularly helpful.
Enjoy and make it a great day!
http://marinesurvey.com/index.html