Ah, the smell of melted wire insulation...

[Jim Marshall]

Ok, electical experts, two questions for you. The other day, after just launching my well-used '88 TV-17, smoke started coming from under the console. There must have been some kind of short, and the insulation was literally melting off of the wires. I found the hottest wire (ouch) and cut it. Smoke stops, everything's cool, courtesy lights don't work, so there's the culprit, right?



Here are my questions...



1) Shouldn't the fuse have blown? I'm in the process of replacing all the fuses now, but I'd like to know what amp fuses you use on accessories, lights, sonar, GPS, bilge, livewell, etc. 5 amp? 10 amp? What do you have in your boat?



2) Could a bad voltage regulator have caused this meltdown? The meter regularly reads 13-15 amps when idling. Could the charging circuit send too much juice, causing a problem like this? I'm changing out all the toasted wiring from under the console (my aching neck!), but I wanted to eliminate the regulator as the trouble spot.



Thanks for any advice...



Jim

 

[Staci Matheis]

J -



Assuming you have the cylindrical fuses (can't remember what they're called) the board or in-line holder will only accept the size that is intended. A board will have the proper amperage printed on it. Those for your console, lights, etc. will be very low; they simply don't draw much amperage.



The regulator is not the problem. Output of 13 to 15 amps is normal.



I would guess that you just got a couple of wires crossed somewhere..... Or perhaps, over the years, someone by-passed the fusing.....



me!

 

[Barry Loos]

The fuse should have blown before the insulation melted. The purpose of a fuse is to prevent a circuit from over heating. Someone might have placed an over rated fuse in the panel for that circuit. I would say that a 5 amp fuse would be on the running lights. Sometimes the insulation gets rubbed off of a wire and can touch a metal object or another exposed wire and develop a dead short. This will blow the fuse. Instead of fixing the problem, sometimes people selling a boat will "over fuse" a circuit so it will work during negotiations. Then again they might have thought they put the right one in the panel and then it was fixed. Anyway, right or wrong fuse, look for what was causing the problem and fix it. Then the smoking wire problem will go away.



Good Luck



Bear

 

[Bob G.]

Jim,



If you have a voltage/ohm meter, you can use it to track down opens/shorts in your wiring. If you don't have one, buy or borrow one. Radio Shack sells some small inexpensive models that will suffice. You may have a circuit that is only partially shorted (medium resistance) to another circuit or ground. I have been doing semiconductor equipment maintenance for 20+ years and a couple of times I have seen wires melted right to a fuse holder without the fuse being blown. I could never figure out why the fuse would not blow, but i would replace the wire with a heavier gauge. Hope this helps. Feel free to send me an e-mail if you have any general electrical questions.



Bob G.

 

[Staci Matheis]

Sounds about right to me!

But I've got a tin ear!



me!