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submersible pump

Discussion in 'Irrigation' started by irg8ric, Sep 4, 2010.

  1. irg8ric

    irg8ric LawnSite Member
    Messages: 29

    Other than using a chart - is there a way to determine if power wire to pump is too small?
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 49,449

    Too small? For 8 amps you don't have much to worry about.
  3. 1idejim

    1idejim LawnSite Fanatic
    Messages: 10,471

    yes, but how far are you talking about? if the pump was installed by a well contractor the wiring should be suffecient to accomondate the length +20%

    how old is the pump and is the controller sitting in southern exposure/full sun?


    this calculator is as handy as a shirt pocket. to get the length of the wire i'd use my TDR but you can measure or step off the estimated distance
  4. irg8ric

    irg8ric LawnSite Member
    Messages: 29

    First off, thank you for the input.

    I am assuming the reason the pump kicks on and then kicks off is the overload protection. Below are my thoughts on the matter - please reply.

    This can be caused by: too small of wire, low/high voltage, or high ambient temp. After reading more about pumps - I am leaning towards a wiring issue - or maybe the overload protection on the pump is faulty.

    Wire size is ok - #10 with app. 400'. however - the #10UF is plugged into a outlet - as opposed to being direct wired to the circuit.

    Also, the relay adds a splice and there is a splice at the pump. In addition, the controller (rainbird esp modular) is powered by taking a leg of the 240v from the hot side of the psr.

    I would like to rule out the possibility of this problem being caused by wire size (or too many splices) Can this be done?

    Also, is there a way to determine if the overload protection on the pump is good?
  5. irg8ric

    irg8ric LawnSite Member
    Messages: 29

    pump was installed 2003. controller is not in full sun
  6. bcg

    bcg LawnSite Bronze Member
    from Tx
    Messages: 1,861

    Is this a new problem? Lets start with the basics, is there a pressure switch that's cutting it off? If not, sounds like you might have an oversensitive thermal overload protection relay or the pump is actually getting hot.
  7. 1idejim

    1idejim LawnSite Fanatic
    Messages: 10,471

    1 conductors per phase utilizing a #10 Copper conductor will limit the voltage drop to 2.87% or less when supplying 8.2 amps for 400 feet on a 240 volt system.
    For Engineering Information Only:
    30.0 Amps Rated ampacity of selected conductor
    1.1417 Ohms Resistance (Ohms per 1000 feet)
    0.05 Ohms Reactance (Ohms per 1000 feet)
    7.199999999999999 volts maximum allowable voltage drop at 3%
    6.884. Actual voltage drop loss at 2.87% for the circuit
    0.9 Power Factor

    you can get an electrican with a megger to troubleshoot for you, you can call the installer for input, you can take temperature readings with an ir thermometer.
    to me 30 seconds is not long enough for the pump to get hot if it's in the water, the box on the other hand, may be in direct sunlight and the switches may have gotten hot and been damaged.
  8. irg8ric

    irg8ric LawnSite Member
    Messages: 29

    no pressure switch
  9. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 22,749

    When I was at Maxi-Com school, the megger was considered a essential instrument to check and prove grounding. We just fried the electronics on a on-demand cistern system and I'm wondering why the breaker (220) did not trip before the smoke and smell.
  10. irg8ric

    irg8ric LawnSite Member
    Messages: 29

    oversensitive overload protection - would this mean a new pump?

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