project needs re-wire and last owner had a mess!!

[dvbilous]

Hello, I have an issue with buss bars! There are 4 large ones and one 3 screw small one. All wires are different colors. Is the best way or rather the only way to figure out this mess is rip out the walls and trace each wire? Sound right that 2 bars are neg and 2 pos? and small one ground? Any advise would surely be helpful........ ANY ADVISE!

[CatBuilder]

Step back and take a deep breath. Get your meter out and start testing things. Are you absolutely certain you are not dealing with AC power on any of these busses? It can kill you, so best to be sure.

If it's all DC, just start by turning off everything at the switch panel. Then... turn ONE circuit on and trace it. It just takes a little time looking through the wiring. Label wires if you like. Usually (hopefully) things will be wired in a way that makes sense. Bus bars are great things for organizing wiring projects that would be a mess otherwise.

If the boat is wired correctly on the DC side, there is no "ground", only positive and negative with negative also tied to the engine block. If you have a set of 3 busses or wires, you may have "hot", "neutral" and "ground" and that one (AC) can kill you. Watch out.

So what is the problem then? Are you just trying to learn the boat's electrical system, or are you having some electrical problems?

[dvbilous]

Hello, no this a project boat for a year now and everything else is new so have new equipment but the wiring is just cut off on some of the buss terminals and i know others are live that do not go anywhere. guess i am wondering if i should pull out buss bars and wire and start over with a fuse panel that the boat currently does not have. I have to say that electrical is Not my area and kind of looking for the best but easy way to put lights etc in a boat without not really understanding how buss bars work. is 1 buss usually pos and all wires poss from say vhf sounder go on that one then another all neg go on then back to batt?

[Ike]

As Cat said, Step back, take a deep breath and then get yourself a meter, a pen and some paper.

You don't have to rip out the walls. You need a Volt Ohm meter (you can a good one at any hardware store) with one really long lead. Do simple continuity tests. Put the meter on OHMs. Hook the long lead to one end of the wire (at the panel). Go to what you think the equipment may be and touch the other lead to the wire. If it's the right wire the resistance will be zero or near zero. If it's more than 1 or 2 ohms it's the right wire but there is a bad connection somewhere or the wire needs to be replaced. If its the wrong wire the resistance will be infinite.

First. Four Buss Bars. One is probably DC negative. Another is most likely DC Positive.

The third and Forth may be AC.

BUT as was said, be careful. AC can kill

Next, all those colors mean something.

DC is red on the positive side from the source of power (battery) to the Buss Bar.

DC is Black on the negative side From the source of power to the buss bar and through out the system

Other colors are feeds to different equipment. Look at color codes here http://newboatbuilders.com/pages/elect5.html

AC: again don't touch. Make sure the power is OFF.
AC hot side is Black, Neutral (also very hot) is white. Green is ground and should not have any current in it at all. If it does you have a serious problem.

For DC Start Tracing from the Battery to the Power Panel. After the battery the first thing you should encounter is a big Battery Switch. After the Battery switch should be a large fuse or Circuit Breaker. Then from there to the panel.
That will tell you which in the panel is DC.

Then go from the power panel using colored wires, There should be a fuse or circuit for each piece of equipment in the power panel or near it. There should also be a switch panel for some things like Nav lights. Hopefully the switches are labeled. Label each wire on both ends. Just use a piece of tape and a marking pen.

DCC makes a complete circuit with two wires, color is positive (out ) and black is negative (return)

Do this for each circuit on the positive side. Draw a simple block diagram (It doesn't have to be sophisticated), just a box labeled with name of equipment and color of wire.

Repeat for negative side.

It's a lot of work but at the end you will have labeled wires and a diagram of all the wiring.

Do the same for the AC side, but make sure the power is OFF. This should be easier than the DC because you probably have far less AC equipment than DC. Each piece of equipment should have a Black wire, white wire and green wire. Same for AC outlets.

If it gets too confusing, hire an ABYC certified marine electrician to sort it all out.

[dvbilous]

WELL thats what i needed to hear!!! CATBUILDER AND IKE, thank you!!! as ive been told if you make a mistake could be a fire or really harmful to me! There is a reason I was not asking questions about fiberglass etc.. but as i have said this is a field i really do not know much about! Thank you.. I shall start 2 morrow.

[Ike]

I suggest you do some reading in your spare time Basic electricity http://newboatbuilders.com/pages/electricity1.html

a reading list. Anyone of these will do.

Boatowner's Mechanical and Electrical Manual, by Nigel Calder
The 12 Volt Bible, by Miner K Brotherton and Ed Sherman
Boating Magazine's Powerboater's Guide to Electrical Systems by Ed Sherman
Sailboat Electrical Systems, Don Casey, 1999 International Marine
Boatowner's Illustrated Handbook of Wiring, by Charlie Wing
Your Boat's Electrical System, by Conrad Miller and E. S. Maloney
Managing 12 Volts, Harold Barre 1997 Summer Breeze Publishing

[gonzo]

Getting a remote wire tester is a good investment. They inject high frequency which you can detect at any point in the wire. They can be used in AC and DC circuits.