I wouldn't call boat wiring
dangerous per se, but then again I also know some folks who simply shouldn't be allowed to pick up hand tools, either. For a newbie I would suggest a few pointers:
Assume all wires are live, all the time, until proven otherwise. With AC wiring
it can easily kill you, with DC wiring you can literally blow a finger off if you are wearing a ring and it shorts out battery cables
. So, you make a point to remove all metal jewelry before doing electrical
work. And to disconnect the cables
at the power source, whether that means disconnecting shore power
, unplugging the inverter
, or removing at least one of the battery
Diagramming things, even if that is just a pencil and a big sheet of paper with hand-drawn lines and notes for colors and connections, is priceless when you come back later to try figuring out "what's this wire". Labels are great, although personally I've found many either fall off, fade, or turn black after a few years. Color coded wires solve that problem, but that means an investment up front in multiple spools of colored wire. It pays off in the long term.
There are plenty of good books
, plenty of web sites from suppliers to get you started on "what goes where" but I also find that if you plan it, draw a diagram, and then just stick that on the wall for 48 hours, sometimes you get a better idea and make changes.
And then there are the tools and bits. Do not buy a $5 crimper, buy a good one. (Threads on that.) Do not buy the no-name electrical
tape and fittings, buy the good brand-name stuff. In the long run it is always cheaper to buy and use the good stuff!