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Thread: Sub Pump wiring

  1. #1
    DIY Junior Member
    Join Date
    Jul 2009

    Default Sub Pump wiring

    Currently I have a well 375' from the house. It is supplied via it's own meter from the elect. co. The entire electrical system is about to be condemmed. The overheads run through trees etc. I also need to replace the piping from the pump to the house.
    Getting rid of the meter will save me $180 per year in facility fees.
    The pump is a 1/2hp 110v. I plan on replacing it with a 220V 3/4 hp next summer.
    I need to install the new piping now so plan on running new electrical wiring now as well, while I have the trencher. So the pump will run off the house's electrical service eliminating all other wiring to the pump. I have a new 200 amp service at the house.
    With a 3/4hp 220v pump I can use #12 as it goes 480'. I will use a breaker box at the pump as well as a disconnect.
    Is there any economical options to use the existing pump on the new wiring? It is too long a run for 110v using #12. I would have to go #6 but the price is out of sight.
    I will be using UF cable and burying it 36" down. What is the proper way to permanently splice underground? Can I use crimp sleeves and epoxy filled heat shrink? Or do I have to try and find one run of wire? I'm rural so don't have the options of the big city.

  2. #2
    Architect Spaceman Spiff's Avatar
    Join Date
    Aug 2004
    Salt Lake City, Utah


    Looks like you need a #6 wire for the distance and voltage drop, not to mention the drop of cable down the well pipe.
    I would run 1-1/4" PVC conduit 36" underground next to the water pipe and pull in #6 THWN conductors. Then you don't have to worry about code violations regarding depth. I'd look up the burial depth but my code book is at home...
    Spaceman Spiff aka Mike

  3. #3


    Do NOT run 400' of UF cable. You are asking for trouble.

    Install 1" PVC (about $200) and #6 wire minimum.


    Do NOT make splices underground. Again, that's just asking for trouble.

    Install this circuit properly and it will work for your grandkids. Cobble it together and you will hate your life.

  4. #4
    I&C Engineer (mostly WWTP) Lakee911's Avatar
    Join Date
    Aug 2005
    Columbus, OH


    You may want to consider running Aluminum type XHHW wire in PVC conduit. That might be your cheapest option.


  5. #5
    DIY Member Ford2001's Avatar
    Join Date
    Sep 2009
    Manchester, Vermont

    Default voltage drop calculactor

    To: 220/221

    Me like the "Voltage Drop Calculactor" you posted.

    Where its saids: "enter 1-way circuit length in feet"

    Is it adding another 100 feet, if the one-way circuit length
    is 100 ft. ? I believe it would.


  6. #6


    Don't forget the ground the well casing
    My answers are based mostly on the ICC codes. Advice given is my personal opinion and every person performing work should acquire a permit from his/her jurisdiction and get the work inspected. My opinions are not directions to follow for DIYs or professionals


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