Re: rewiring a prodject
Look at my diagram again. It shows you in as simple a manner as possible "how" things are wired. "Where" each item goes is up to you. I can't tell you where things are physically located in your boat because I don't know what devices you have or plan to have. You cannot tell an electrician to wire your house if you don't tell him/her where you want outlets, switches, and what fixtures you want. Without that information we can't help except to provide very general information. So lets start again but I will answer your gauge question first. NO! Gauges do not connect to the fuse panel. They are powered from the ignition switch which is part of the engine harness which is the electrical cable that runs from the engine to the shift/throttle control box. You do have one those don't you?
Batteries: You need one to start the engine. Boats have been fitted with one battery for many decades so two or three are not necessary unless you have a trolling motor or some other very high power accessories. If all you have is a radio, a few lights and maybe a fish finder, you don't need two batteries. Before we go any further, do you or do you not have an engine and control box for this boat. If so, what year make and model?
The starting battery needs to be installed close to the engine so that means it goes at the back of the boat within reach of the big battery cables that connect to the engine. There are no fuses or circuit breakers associated with the engine except for the one under the engine cover. From here on follow along using my diagram.
Two #8 gauge wires (one red and one black) connect between the battery and the fuse panel which is located at the console. A 20 amp circuit breaker is attached to the positive post of the battery. The other terminal has the red wire connected to it. Only two terminals on a circuit breaker and it doesn't matter which connects to the battery and which one the red wire connects to.
At the fuse panel the red wire connects to the +12 volt buss. A buss is simply a single connection that ties one side of all the fuses together. The other side of each fuse goes to a switch or to some other device. The black wire from the battery connects to the ground buss. Again, this is simply one spot where all of the ground wires "from" each device connects.
All switches on a boat are basically wired the same except for your NAVIGATION/ANCHOR lights which are the geen/red light (NAV) at the bow and the white light at the stern (anchor light). This takes a special switch and wiring is as shown below in two diagrams depending on which type of switch you have.
This is a six pole switch (six terminals). The switch is OFF in the middle, and ON in the UP and DOWN positions. UP turns on both the NAV and ANC lights. DOWN turns on only the ANC light.
This is a simple three terminal switch but it does require use of a diode available at Radio Shack for less than a buck. Switches are available right here on IBoats. There is nothing special about switches other than you need marine rated as they are subject to lots of moisture. Buy what suits your fancy.
Here is a diagram of how current flows through a simple circuit. Think of it as water flowing through a pipe from a bucket. It goes down the red wire, through a fuse, through a switch (valve) through the device or devices and back to the bucket on the black wire. Just follow the arrows. All circuits are wired this way.
The number of switches you need is simple to figure out. What do you need to turn on and off? Whatever that number is is the number of switches you need. All of the switches should be located at the console because that's where you will be sitting when driving the boat. As I mentioned before, if you use a fuse panel (fuse block) as I've shown in my diagram, you don't need circuit breakers.
My last bit of advice would be for you to head to your local library and check out a book on "Low Voltage Wiring Basics". This has nothing to do with boats, but the concepts for boat wiring are basic low voltage. I've now gone as far as I can go not knowing what you plan to install in the boat, what gauges you have, what you will be adding, trolling motor or not, fish finder or not, radio or not, interior lights, live well, bilge pump, and any other things I didn't mention.
