Emergency Wiring Question

Discussion in 'Power it up with Electronics' started by FSUfisher, Apr 21, 2011.

  1. FSUfisher

    FSUfisher Well-Known Member

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    So I took it upon myself to rewire my boat this week. I had originally done all the stuff one thing at a time so I wanted to clean everything up and correct all the annoyances I created in the past. My battery is in the back of my skiff, so I ran 10 gauge marine wire from there to my console, which is about ten feet. It goes into a battery on/ off switch, then to a bus panel. The bus panel goes either to the switch panel for all those switchable components (bilge, lights, etc) or to the stuff I want directly connected (radio, depth finder, etc). I also ran 10 gauge wire from the bus terminal to my ground point, about two feet away. Of course, the switch panel is grounded to the same point, as are all the components I have hooked up (or so I think, as it is now dark out). The ground point has another ten feet back to the negative terminal on the battery, bridged with more 10 gauge marine wire. Everything else has been wired with 14 gauge.

    When I hooked everything up to test for power, the positive 10 gauge wire began to burn up fast as I discovered there was clearly a short. By the time I had gotten it disconnected from the battery, the negative 10 gauge wire was completely shot as well. Let's just say that was one of the scariest moments of my life, and my lungs are still burning from the electrical smoke. Luckily I must have fused all my components properly, for all other wires seem fine. I don't know about the actual components yet.

    Does anyone know off hand what could be the problem? Was I not supposed to ground my positive bus panel? I realized after everything happened that I may not have tightened the nut that holds all the negative wires together to the bolt that is my ground point. But in that case, I wouldn't think the negative cable would also burn up. Please help so I can get this corrected in time to fish this weekend!

    If it helps, I can draw a crude picture of my setup. I have elementary electrical engineering knowledge, but unless I made a stupid oversight in my wiring, it must not be enough.
     
  2. Brett

    Brett > PRO STAFF <

    Heavy gauge from positive terminal to positive buss/fuse bar/switch panel
    then feed smaller gauge to individual accessories,
    and from accessories back to ground buss bar,
    then heavy gauge back to negative terminal.
    Kind of like the cooling system in the car.
    Big hose from water pump to radiator inlet
    where flow is spread through small passageways of radiator
    back to collector side of radiator and big hose back to block.

    previous post with diagrams

    http://www.microskiff.com/cgi-bin/yabb2/YaBB.pl?num=1250548769


    Did you really run a wire from the positive bus back to the negative terminal? :-?
    If so then you literally connected the positive terminal
    direct to the negative terminal with no intervening circuitry.
    You're lucky you didn't smoke your whole boat... :eek:
     

  3. FSUfisher

    FSUfisher Well-Known Member

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    Wow, that's it Brett. There are two larger studs on my positive terminal, and I thought I had heard somewhere that the terminal itself needs to be grounded. When things got squirrely I first flipped the main power switch off, then had a hellacious time trying to spin the wingnut off the battery to remove the positive wire amongst the fire, smoke and flying sparks. Luckily, I believe the only casualties are my two main wires but I'll have to check further tomorrow.

    Unfortunately, elementary electrical engineering is not enough, as I don't completely comprehend why the wiring is not acceptable.

    Thanks Brett!!!! [smiley=1-thumbsup1.gif]
     
  4. FSUfisher

    FSUfisher Well-Known Member

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    Nevermind my previous post Brett. After a little bit of thought I now realize how asinine it was to wire my setup the way I did. Hopefully there will come a time in my life where I don't act as reckless; I had reservations about how to wire the positive bus panel but instead of asking, or even thinking rationally about the solution, I just went along my merry way. I guess it's the impatience land lack of focus. Anyways, I've got someone to thank before I go to sleep for the fact that I didn't just burn my boat to the ground... :-?
     
  5. Brett

    Brett > PRO STAFF <

    Install a 50 amp circuit breaker between your positive terminal
    and the positive buss bar to prevent this from happening again.



    I do not understand why battery manufacturers still put wing nuts on the terminals.
    Just about the stupidest thing they could do. Wing nuts do not do an effective job
    of securely fastening the lugs to the posts in a manner which will prevent loosening.
    When the wing nut loosens it allows the cable lug to shift position
    and causes intermittent contact with the post. This can lead to arcing
    and wiring/terminal melting. That's a major fire hazard on any vehicle.
    Get rid of the wing nuts, replace them with stainless steel ny-locs


    This has been a public service rant, brought to you by the school of hard knocks... ;)
     
  6. firecat1981

    firecat1981 BBA Counselor

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    FSU are you planning on running a trolling motor? if so you might want to upgrade that 10 ga. I'm running 4 ga. for my battery cables.
     
  7. FSUfisher

    FSUfisher Well-Known Member

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    Good idea Brett. I never thought of the wing nts coming loose and I'll make the upgrade ASAP.

    Firecat, my troller runs on it's own battery up front. I can't imagine 4 ga. wire! I have a hard enough time finding hardware for 8 ga. wire!
     
  8. firecat1981

    firecat1981 BBA Counselor

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    That's funny, cause I have a easier time finding stuff for 4ga and above. The little connectors are a pain to find.