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blueh20's avatar
blueh20
Explorer
Oct 21, 2018

10ga or 12ga help wanted

I am mounting a new flojet water pump on my 2014 ford e250 conversion, the pump says 7.5 amps at 50psi.

The instructions that came with the flojet says to run 12ga up to 50ft.

I have a 23' run, thats from the battery thru the fuse block to the switch then to the pump.

running 8ga from battery to fuse block which is 5' away, running a 30amp breaker on the fuse bloc.

I was planning on running a 10ga loop which equals 46', the 3 elec. male slide on connectors built into the switch are to small to attach 10-12 ga female connectors to, they wiggle when attached and are too narrow for a good fit.

The other option is to just run the 12ga for the 23' and ground the pump to the vehicle right next to the pump..

All my other wiring in the conversion I have done as a loop back to the fuse block.

Blue Sea systems chart says 8ga for a loop. Most charts say 10ga for a loop and found one that says 12ga loop.

Looking for input and comments from experience..

thanks
  • blueh20's avatar
    blueh20
    Explorer
    Oct 22, 2018
    thanks for answering my question folks, some great ideas how to make the 10ga work. Trimming a few strands or pig tailing smaller wire on the switch.
    My original post I messed up on, the 30amp breaker controls the fuse box, the pump will be on a 10 amp fuse.

    guess 10ga it is. thanks
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Oct 22, 2018


    DELCO PACKARD 56 terminal

    The only Fast-On terminal worth snot. It does not fit loose, get loose or overheat.

    You'll have to crimp the closest terminal to the copper stands then the 2nd terminal to the insulation. It's a tight fit but this is an automobile manufactuer's preferred terminal because it works. The header says 12-gauge I've connected hundreds to 10 gauge.

    I've not seen counterfeits of this connector. A bit pricey but worth every damned penny. I REFUSE to use snot grade fast-on terminals after getting burned by connector failure.
  • Dusty_R's avatar
    Dusty_R
    Explorer
    Oct 22, 2018
    Just use stranded wire and clip however many strands until the crimp on lug will fit.

    Dusty
  • goff1256's avatar
    goff1256
    Explorer
    Oct 22, 2018
    I ran 8 gauge wire 30 ft to a relay then my water pump and
    my furnace what a difference
  • tenbear's avatar
    tenbear
    Explorer
    Oct 22, 2018
    Here is a good chart for calculating the wire size for a given current and wire length. https://www.bluesea.com/resources/1437
  • BFL13's avatar
    BFL13
    Explorer II
    Oct 22, 2018
    Use fatter wire where possible. You can pigtail thinner wire from the terminals that will only take thin wire onto fatter wire just after that.

    Water pump coming on that causes more voltage drop can be a problem with a small inverter that has thin wires too, so it can just barely run the TV/DVD. Water pump comes on and knocks out the inverter for low voltage.

    Mostly otherwise with a good set-up, who cares if the water pump drops the voltage? It only runs for brief times, so it just doesn't matter.
  • RJsfishin's avatar
    RJsfishin
    Explorer
    Oct 22, 2018
    Yep, run 30 amp wire to carry 10 amps max. 14ga is good, 12ga is over kill, so 10ga really makes sense :)
  • old_guy's avatar
    old_guy
    Explorer
    Oct 22, 2018
    you can't go wrong using 10 gauge wire. you will have less resistance and better flow to the pump and the wires will not over heat or drop voltage
  • enblethen's avatar
    enblethen
    Nomad
    Oct 22, 2018
    Why are you talking 30 amp breaker? Breaker should be in the neighborhood of 10 amp for the pump.
    You should be able to run and use #10.
    Switch should have 1/4 terminals. A yellow female should connect very easily.

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