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Thread: Square D well pressure switch

  1. #1

    Question Square D well pressure switch

    I was checking my well pump pressure switch to determine if it could also control a booster pump.
    I found out that the switch was cross wired wrong,that is when the pump is off the motor terminals have 230 volts and lines 1 and 2have zero volts.

    Since the well has operated that way for 10 years I beleive that the pump starter control input was also crossed to undo the mistake.

    Is it ok to leave it as is? Does this affect the contact points?

    Thank you in advance for any info.


  2. #2
    Sprinkler Guy Wet_Boots's Avatar
    Join Date
    Mar 2007
    Metro NYC


    The pump switch has DPST contacts, so one side is as good as another, so far as the electricity goes.

  3. #3

    Default Square D well pressure switch

    My thanks to Wet Boots.
    I will leave well enough alone since it is working.

    If I hook up a booster pump to the same pressure control I believe I should follow the same convention. The total ( combined) load will be 1 hp and the switch has a capacity of 2 hp at 230volts.


  4. #4
    Electrician frenchelectrican's Avatar
    Join Date
    Jun 2007
    NE Wis / Paris France { In France now }


    It can be done this way but really IMO if you want to do this in right way you have to make a junction box after the pressure switch.

    before you do this make sure the power is off first before you do this because the pressure switch can kick on without warning and get ya a nasty cussing for a while.

    run a short piece of wire it have the same size as incomming power wire is 14- 14 or 12- 12 gauge size.

    that point if your well have just a standard run of mill 2 wire control just hook up the junction box [ best to use 4X4X2 1/8 ] and have one wire from pressure switch to the junction box and get the wire from the well pump get that in the box and also the booster pump and splice the wires excat same colour black to black red to red if have it and white to white [ this have to be remarked for 240 volt useage ] and MAKE SURE the ground wire is well tied well after that put on the blank cover on it and mark it on cover to tell what the wires go for say like this " well pump " and "Booster pump"

    this way it will make it easier to do this

    do not try to make a extra splice in the pressure switch there is no room for third cable in there at all

    Merci , Marc

  5. #5
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Cave Creek, Arizona

    Default wires

    splice the wires excat same colour black to black red to red if have it and white to white

    Why? All the electricity I have ever worked on has been color blind and does not know which wire it is using. A properly wired switch would not break the neutral so if the switch has two wires it is probably 220/240 volts.

  6. #6

    Default Square "D" well pressure switch

    My thanks to Frenchelectrican and HJ for the detailed instructions and safety guide lines.



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