Help! Electrical Problem

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R

Roy

No previous elecrical problems. Yesterday I swithed my battery switches to on and and smoke began to pour out from under the nav table and battery compartments. I killed the switches immediately but not before a black 16ga. wire from the neg. side of the battery to the ground side of the stereo panel switch nearly burned up. I have no stereo onboard and there was no fuse in the panel, In addition, 8-10 small 10ga. wires in the panel at the nav station virtually melted. Not much info to you but does anybody have a guess as to what happened? If I replace without knowing the cause, I may have to do over again and again...Thanks to any of you sailers that can hazard a guess or know for real. This is a Cat30 with a 4 battery set-up.
 
C

cole

Need more information

Did you replace any battery in the box? was any rewiring done? Sounds like a battery was put in backwards, with the info we have now.
 
G

Guest

wire chafing

sounds like wire chafing i maybe wrong but if you have had this boat for a while and no problems i would start there.
 
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Bill Doyle

A Question for You

Roy, Sorry that I don't have any help or advice to to offer but I have a question for you. My wife and I have looked at the Oriental area for retirement, a few years away, and would be interested in your comments on the area. So after you get you electrical problem sorted out, I'd appreciate your thoughts on Oriental. My email is lesdoyle@aol.com. Bill
 
R

Roy

Help.

Tx. for the response. I installed a depth sounder since the last time the boat batteries were energized. The leads from the depth sounder were attached to the appropriate battery post. When the batteries were turned on , I did not have the wires to the depth sounder plugged into the unit itself. Roy
 
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Ernie Rodriguez

Faulty circuit

You will have to look for the faulty circuit that caused the problem, but after you find it and correct the problem, the next thing you should consider doing is to install a correctly sized circuit breaker on the bus wire that leads from your batter switch to the power panel. The circuit breaker needs to be sized for the wire size and mainly to protect the wire for problems like you just experienced. In fact any wire that leads directly from the battery positive post should have either a fuse or resettable circuit breaker in line, and as close to the battery, again sized for the wire, not the load. If the correctly sized fuse will not handle the load, then the wire size is inadequate for the load. I have seen several wiring systems where the fuse is located far downstream from the source of power, the bttery, that a short in the wiring can lead to a fire or severe problems. Check it out carefully as you were probably lucky that you were able to terminate the problem by opening the circuit with the battery switch, but in other cases you may not have a choice and the end result could be a fire. Good luck with it. Ernie
 
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Duane Cady

Get a Multimeter

Hi -- Troubleshooting wiring problems in most cases requires a multimeter. These days you can get one fairly cheaply at radio shack. A short in the wiring that would cause this kind of issue usually means that somewhere, the negative (or ground) side of the circuit got connected directly (not through an appliance or 'load') to the positive side of the circuit. In that case, the current draw will be so great that it will burn up your wiring. To troubleshoot, first look for hot-spots. Places where it seems there was more heat than others. Likely you will find wires virtually welded together, or to a ground source, like the faceplate of the breaker panel. Something like this would likely be the source of the problem. Another way is to disconnect the batteries at the post, then put your meter (in the ohms position) across the positive and negative battery terminals. If the meter reads 0, thats a dead short. Move up the line to the next place it connects (breaker panel, batt switch, whatever), isolate the 2 circuit runs (the one back to the batt and the one forward of the batt switch or whatever) and measure again. A dead short (0 on the meter) on the battery side means its someting back towards the batteries. A dead short forward, and you have to go forward and isolate the circuit, probly at the breaker panel. At this point, it should be fairly easy to isolate the individual circuits that run the appliances in your boat, but turning the circuit breakers 'off'. Of course you have to be careful that it isnt your battery or a particular CB that is shorted, although Ive never seen that happen. Its not as complicated as this might sound. Just remember that current flows from neg to pos, and needs to flow through a load (like an appliance or light). If it has a path directly from neg to pos, thats a short circuit, and it /will/ take that path. Your mission is to find that path. Hope this helps. Duane
 
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Duane Cady

Oh... Addendum...

By the way, If the circuit is as it should be, you should not read 0 -- you should read whatever the resistance is of the load, or infinity on the meter. Duane
 
G

Gene

Fuses

Ernie gave you the key information that is often overlooked. Not what started the problem, but why did it happen. If fuses are properly installed (right location, right size) you should never have a melt down. If a short developed, which happened somewhere in your case, the approprate fuse would blow. The fuse must be sized to protect the user, and the wire sized to safely carry that load. Don't know if you will ever find the cause, but my first guess would be items added by non-electricians (stero?)
 
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Duane Cady

Regardless of fuses...

It would be great if he had fuses right after the hot comes off the battery -- but apparently he doesnt. The problem at this point is that where ever its shorted, a fuse isnt blowing. Before he can even use his 12v system, he needs to try to isolate the issue. If its burning up wiring, I would suggest that the problem shouldnt be too hard to find. I would suggest starting with his wiring that he has added -- if your not careful in wiring using splices, or solder, or whatever, you could leave some bare wire hanging out in the back of the cb panel, in the batt compartment, or where-ever, just waiting to touch the wrong polarity. Another problem with splices is if you dont crimp them securely, and one end pops out and wreaks havoc. This can also happen to an old splice just by the act of pulling the cb panel out to add other wiring. For future reference, definitely fuse and/or breaker of the correct sizes for the load. Duane
 
C

cole

try this

remove the wire from the battery posts and attach a DVM, set the scale for M Ohms Your reading will most likely be 0 with the switch on. Then start disconnecting items like the new sounder untill the meter goes to inf... this reading is the desired one. I use the buzzer setting untill i cant hear the noise. Look for me in Oriental this Weekend aboard the Bobs Degree. Id like to meet. Cole
 
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