Boat fuse block?

  • finman
    Posts: 277
    February 19, 2012 at 5:10 pm #1238783

    I’m looking to add a couple fuse blocks into my boat to clean up some of the wiring, and take many of the terminals off of the battery posts. What size fuses should I use?

    thebigd25
    st. paul
    Posts: 124
    February 19, 2012 at 5:38 pm #1040615

    You should use the size recommended for the appliance. My locator circuit is a 1/2 amp fuse and the nav lights have 5 amp fuses. The spot lights I have are on 10 amp circuits.

    dank
    Minneapolis, MN
    Posts: 1123
    February 19, 2012 at 6:15 pm #1040624

    Finsman-

    Let me know what you find out and decide to get. i am looking to do the same thing as I have too many wires going to the batteries. that are connected with fuses

    Thanks

    finman
    Posts: 277
    February 19, 2012 at 6:22 pm #1040626

    DanK-

    Will do- it sure is a pain in the trying to figure out what goes where, under my driver’s console looks like a plate of spaghetti- wires everywhere!!

    eyekatcher
    Lakeville, MN
    Posts: 968
    February 19, 2012 at 10:36 pm #1040675

    I went with two of the blade type 5 position blocks
    They are much easier to read if you have to replace one.
    They are also color coded.

    joshbjork
    Center of Iowa
    Posts: 727
    February 20, 2012 at 11:14 am #1040758

    I just stuck one of those fuse blocks in my truck. Seems ok.

    dank
    Minneapolis, MN
    Posts: 1123
    March 30, 2012 at 12:17 pm #1054133

    We are in the process of re-doing our wiring and will be using this to clean up the wires around the batteries. we are pretty happy with it and it will make it look a lot nice and organized.

    http://www.johnnyraysports.com/terminals.htm

    TheFamousGrouse
    St. Paul, MN
    Posts: 11804
    March 30, 2012 at 1:45 pm #1054196

    Quote:

    You should use the size recommended for the appliance. My locater circuit is a 1/2 amp fuse and the nav lights have 5 amp fuses. The spot lights I have are on 10 amp circuits.

    In addition, keep in mind that you need to use wire of the gage that is appropriate to both the amperage draw of the devices on the circuit AND adjusted to compensate for resistance imparted by the distance of the wire run.

    It doesn’t do any good to have a 15 amp fuse if your wire can only support 10 amps when the resistance of the run and the load is factored in. In that case, your wire will BE the fuse.

    With boats, people tend to chronically underestimate what the proper wire size is and very few actually bother to figure it out. I don’t know if people are just cheap and when they see the price of 12 gage wire, they just grab the 18 gage instead or what?

    I’ve seen dozens of bilge pumps running off of 18 gage wire where the pump is a 12 foot wire run from the switch. Oh yeah, it’ll still work. Until that time you take a big green water wake over the side and have to run the pump under load for 20 minutes and then the wire is going to burn up.

    Also, if your wire is undersized, you are losing the efficiency. A bilge pump that is being strangled by undersized wire might pump at only half or a third of the rated capacity. So while you think you have a 1200 GPH pump, in reality by the time you factor in the rise, the hose resistance, and the wire resistance, you might be able to only actually pump 400 or less gallons per hour.

    Bottom line is to size everything correctly. Battery to block, fuses, and then block to device. It costs only a few dollars extra to do it right.

    Grouse

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