Grounding practice on 12V circuits.

Discussion in 'Electrical Systems' started by 60Mandalay, Nov 28, 2014.

  1. 60Mandalay
    Joined: Nov 2014
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    Location: Des Moines, IA USA

    60Mandalay New Member

    Hi All, Old timer but newbie to this forum, here.
    Am building a 23' Glen-L design outboard power boat for Day fishing and diving. Am doing the wiring diagrams and circuit protection on CAD at this time and have a wiring practices question.
    We are going to have 3 main ground Buss's in the hull, helm Station, mid-hull, and stern area. All are linked together with #8 wire.
    Question: Let's say a properly protected circuit (+12V) going to the stern area starts out at a helm dash switch and runs aft to the load. Is it proper or common practice for the ground side of the circuit (same wire size of course) to be terminated at the stern ground buss or does it have to go all the way back to the helm area ground buss. Pondering????:?:
    Thanks in advance!!
    Paul M.
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    If you have a common ground it can be connected anywhere. However, the wire should be able to carry the amperage of all the loads connected at that point.
     
  3. 60Mandalay
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    60Mandalay New Member

    Grounding practice on 12V circuits

    Thanks Gonzo, I thought that would be the case. I will insure the load ratings and distance for a 3% voltage drop max.
    Thanks again!!
    Paul
     
  4. CDK
    Joined: Aug 2007
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    CDK retired engineer

    The negative battery terminal is the center for all ground wiring, I expect that to be at the stern. That usually also is the location where high currents flow (starter, alternator).

    If mid hull involves current guzzlers like A/C or fridge, the ground wire should be connected to the battery as well. Same goes for a bow thruster if you planned that.

    The helm ground buss does not carry high currents, so it can be the last part of the chain.
     

  5. 60Mandalay
    Joined: Nov 2014
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    Location: Des Moines, IA USA

    60Mandalay New Member

    Hi CDK,
    In this case, a large single AGM battery is midships for balance with heavy 2/0 leads to the transom for engine start etc... Actually only 8 ft of distance.
    Thanks for the insite CDK, we'll be aware.
    Paul
     
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