Thanks- would you have a wiring diagram for that same boat- just bought the 77 22' O'Day- needs some work, No Juice to the Main Fuse panel.
Appears former owner ran the main red/black to the port cabin bunk area, than tied in his radio, nothing else.
I've examined the wiring in my boat pretty carefully. There is a red + and a black -- wire that comes from the battery (Line Side) and goes to the electric panel, or load center. The black is tied in with all the other black wires coming from your lights (Load side) which makes up the ground or negative connection for all the lights and other electric fixtures.
The red or positive wire from the battery is attached to the line side of these breakers or fuses via a live buss bar on my panel. The lights and other electric necessities are connected to the load side of each breaker. I have red and black wires going to each light on my boat. It's pretty simple. The red is the hot wire and the black is the ground.
You may want to put certain lights on one breaker and other lights can be combined together on the same breaker.
For instance:
Your running lights should consist of a bow and stern light. So the red wires from both of these lights will want to be connected to the Load side of one of the breakers and the two black wires from these lights are tied into the bundle of black wires or grounds, near the panel. If you have a lighted compass, you could tie it into this circuit on the same breaker so that it comes on with your running lights. This breaker can be labled, "Running Lights."
If you have a steaming light on your mast, you should put it on a seperate breaker. Steaming lights are placed about 2/3s of the way up the mast and they are used for motoring at night with the running lights. If you are under sail, just the running lights are used.
Your mast head or anchor light should go on a seperate breaker by itself and can be labled, "Anchor light."
Your inside cabin, or dome lights can go on a seperate breaker which can be labled, "Cabin Lights." Your VHF radio can go into this same circuit. Because your radio and dome light have seperate On and Off switches, the breaker can stay in the "On" position at all times.
What you could do is draw out your own schematic based on how you want your electric system to operate with the number of fuses which are available in the electric panel.