Have done a lot of wiring on boats and learned pretty much from zero.
A few suggestions:
1. It's your boat, and you can wire it any way you want. However, there are many good reasons to use "best practices". Most boat fires are caused from electrical issues. Most intermittent or non-working equipment issues are caused from bad electrical connections.
2. Best practices are outlined by the ABYC. It can be daunting to decode all of the raw specifications, but there are plenty of good practice guides available. Bottom line, you want the electrical system on your boat to be safe AND reliable.
Maybe the best reference for anything electrical/mechanical on boats is this book from Nigel Calder:
https://www.amazon.com/Boatowners-Me.../dp/0071432388
3. Visit the Blue Sea Systems web page. Not only do they sell good stuff, but they have a free wiring calculator tool. Simply plug in how much current (amps) your load uses and the length of the run. Poof, the tool will tell you what wire size to use to be compliant with ABYC rules. Don't forget you need the the round trip wire length. I have no affiliation with Blue Sea Systems.
4. You need a way to disconnect the battery in case of an emergency. Usually this means installing a battery disconnect switch close to the battery.
5. Fuses are primarily used to protect the wiring. You need a fuse close to the battery to protect the wire up to your helm panel. Starter motors are exempt from this, but every other positive wire should have a fuse or a circuit breaker. Even the circuit breaker in a panel is there to protect the
wire to the appliance/device. Most equipment will require another fuse for equipment protection. Make sure to wire those in. It may make sense to locate the equipment fuse near the equipment.
6. Wire type. Marine use is a hostile environment for wiring. The good stuff is stranded tin plated copper wire. Ancor is pretty much the major supplier of this. If you have an engine compartment, you need to be aware of the temperature rating of the wiring insulation. Don?t use house wire for wiring a boat.
7. Wire color. I?ve seen many guys use whatever they have laying around. Sure, the electrons don?t care about the color the insulation. You may completely understand your wiring and what goes where right now, but what about in 2 years? What if someone else ever works on your boat? Bite the bullet and use the proper wiring colors for the major circuits:
12V DC positive RED
12V DC negative YELLOW (black is OK, but use yellow for anything new)
120V AC hot BLACK
120V AC neutral WHITE
120V AC safety ground GREEN or GREEN/YELLOW
Bonding wires GREEN or GREEN/YELLOW
8. Wire connections. No wire nuts on a boat, anywhere, ever. Crimp connections are the standard on boats, and they cause a lot of electrical problems if not done properly. You need both good quality crimps and a matching good quality crimping tool. I?ve found this to be the area of much voodoo when wiring boats. When you purchase crimps, there?s nothing about what tool to use. When you purchase a crimper, same thing. You aren?t going to find marine worthy crimps at Home Depot or Harbor Freight. Do some research or crimps will become your biggest headache. Just go here and read.
http://www.pbase.com/mainecruising/wire_termination
Be prepared to pay for good tools and good crimps.
Please, don?t be intimidated. Like anything else, there?s a learning curve. After a few days of reading, you?ll be well on your way to doing a good job.
Best of luck,
?bill