Switch Panel Question

Discussion in 'Electrical Systems' started by WesS, Feb 9, 2010.

  1. WesS
    Joined: Jan 2010
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    WesS Junior Member

    I am wiring up my 14' wooden boat I built. I have read about the grounding issue and plan on sending all negative to the battery. It is a 12V so I should be good? I have bought a 6 switch panel for running, anchor, bilge, floor lights, head lights, and fishfinder. The panel has a breaker switch button for each switch, do I still need a fuse panel? Do I still need to fuse from the battery? Do I still need to fuse to the fishfinder? If so is it best to fuse on positive or negative? THanks.
     
  2. CDK
    Joined: Aug 2007
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    CDK retired engineer

    No, no and no!
    If the switch panel has circuit breakers you have everything you need.
     
  3. WesS
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    WesS Junior Member

    Fuse

    So no fuse to panel from battery or one to fishfinder?
     
  4. jonr
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    jonr Senior Member

    Each wire should have a fuse somewhere in the path that will blow before the wire overheats and starts a fire - ie, the wire size and the fuse/breaker size are related. This rule includes the supply wire from the battery.

    It would be a mistake to wire a fishfinder with small guage power wire to a large breaker. The fishfinder could short out internally and the supply wire could start a fire without the breaker blowing.

    Fuses/breakers near the source are better than further downstream - something could cut into the wire.
     
  5. WesS
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    WesS Junior Member

    So, even though the panel has a breaker I need fuses?
     
  6. jonr
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    jonr Senior Member

    Not necessarily - if I can point to any wire and you can point to a fuse or breaker that will blow before it exceeds its safe current, you are fine.

    On the other hand, if you want to connect a fishfinder with 20 gauge wire to a 20 amp breaker, yes, safer to add a fuse.
     
  7. WesS
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    WesS Junior Member

    thanks
     
  8. CDK
    Joined: Aug 2007
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    CDK retired engineer

    You asked three questions, I gave three answers.
     
  9. kim s
    Joined: Apr 2009
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    kim s Junior Member

    fuses

    Ahh----finalysomething on this wholeforum I know something about:)

    Wess, this I know will seem a daft question---when you say the panel has 6 breakers---do you mean straight switches (on/off) or are they trip switches. ----do they have an amp rating.
    This might be a case of my mis-understanding the American term.
    There are 2 different sorts of panels. one that has a switch AND a fuse and some that appear to just have a switch--these are the fuses as well.
    My only thing to advise is to make sure (as johnr)stated, every wire supplying a piece of kit, MUST have a fuse somewhere. People think the fuse is to protect the kit at the end-----ITS NOT. its to protect the wire supplying the kit. If the wire chafes against a bulkead and shorts out, you want the fuse to break before the cable gets hot enough too catch fire
    so a cable rated at 16amps does not want a 20amp fuse. if the kit fails and shorts out, the cable melts and causes damage before the fuse blow

    One that a lot of people miss out, is the wire that comes from the Battery to the switch panel.(remember the fuse is to protect the wire).

    There are many good books on boat wiring.
    Other tip ----use multistrand cable -not solid core. it breaks fairly quickly due to work hardening. the best cable is tinned throught its length as it does not corrode.

    Kim
     
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  10. WesS
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    WesS Junior Member

    thanks kim. Th switch panel has reset buttons/breaker buttons for lack of a better term and also the on/off switches. Does that help?
     
  11. WesS
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    WesS Junior Member

    First- I did thank him on 2/09. 2nd- thank you
     
  12. jonr
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    jonr Senior Member

  13. Guest62110524

    Guest62110524 Previous Member

    my sincere apologys
     
  14. kim s
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    kim s Junior Member

    That sounds lie they are breakers (fuses/trips) . you should find some where on them the rating . ie 5A , 10A.
    If thats the case, then just connect the wires to your radio etc. You need to put things that use a large amount of electriity on the higher rated fuses. things like nav lights ,or bilge pumps, and things like fish finders, radios , gps on the lower rated ones. Its best to put you VHF/DSC on its own switch, dont connect other things to that circuit so you keep interferace down. also use the largest cable possible for the rating of the breaker, so you dont get a voltage drop, which will effect your output when you transmit for help , cos your boats on fire cos some idiot from UK advised you how to do the electrics:p :p
    I strongly advise you purchase a book on it ,as a picture tells a 1000 words etc, but it sounds like you have a good start to your project.
    good luck
    may all your terminals be nice and tight

    Kim
     

  15. goboatingnow
    Joined: Oct 2008
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    Location: Ireland

    goboatingnow Junior Member

    in-line fuses have no place on a boat in my opnion. Try hunting behind panels to find that forgotten fuse in an emergency.

    Size your panel breakers to suit, anyway electronics fail before the fuse blows anyway.
     
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