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Thread: GFCI Distance Too Far?

  1. #1
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    GFCI Distance Too Far?

    I have a customer that I ran power for his pool pump over a year ago. If I remember correctly, the run is approx. 100'. The circuit is fed from a 20A GFCI breaker. I ran #12 THWN in 3/4" PVC underground. I ran the power to a switch then to a Duplex receptacle controlled by the switch. (All in weatherproof boxes w/in-use covers)
    Now a year later he calls and says the GFCI keeps tripping. Since this customer is a good distance away I tried to help him over the phone.

    He says the pump motor was getting extremely hot to the touch. I told him the GFCI breaker might be tripping on overload rather than ground fault. I said this thinking the pump motor was bad. Then he tells me the dog was getting caught on the cord and damaged the insulation on the cord to the pump. So now I'm sure the damaged cord is what is tripping the GFCI. I told him to either get another cord or a whole new pump as both could be bad.

    Now he calls back and says he installed a new pump w/new cord and tried to run it. He says it ran for about 10 mins. then tripped.
    I know that certain pool pumps won't run on any GFCI other than Siemens. The breaker that I used was a C-H BR GFCI. I don't think it's an issue with the brand or it wouldn't have ran for a year. I'm thinking the distance is what is causing the GFCI to trip.
    Could that be it or what other things might cause this?
    Just trying to be prepared if I have to go back there and check.
    If it is the distance, (100') would it make a difference if I changed to a regular breaker and changed the duplex to a GFCI?
    If you aim at nothing, you will hit it every time!

  2. #2
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    Quote Originally Posted by Little Bill View Post
    I have a customer that I ran power for his pool pump over a year ago. If I remember correctly, the run is approx. 100'. The circuit is fed from a 20A GFCI breaker. I ran #12 THWN in 3/4" PVC underground. I ran the power to a switch then to a Duplex receptacle controlled by the switch. (All in weatherproof boxes w/in-use covers)
    Now a year later he calls and says the GFCI keeps tripping. Since this customer is a good distance away I tried to help him over the phone.

    He says the pump motor was getting extremely hot to the touch. I told him the GFCI breaker might be tripping on overload rather than ground fault. I said this thinking the pump motor was bad. Then he tells me the dog was getting caught on the cord and damaged the insulation on the cord to the pump. So now I'm sure the damaged cord is what is tripping the GFCI. I told him to either get another cord or a whole new pump as both could be bad.

    Now he calls back and says he installed a new pump w/new cord and tried to run it. He says it ran for about 10 mins. then tripped.
    I know that certain pool pumps won't run on any GFCI other than Siemens. The breaker that I used was a C-H BR GFCI. I don't think it's an issue with the brand or it wouldn't have ran for a year. I'm thinking the distance is what is causing the GFCI to trip.
    Could that be it or what other things might cause this?
    Just trying to be prepared if I have to go back there and check.
    If it is the distance, (100') would it make a difference if I changed to a regular breaker and changed the duplex to a GFCI?
    The damaged cord likely had broken strands of wire, effectively decreasing the AWG and causing the motor to overheat - much like running one on an undersized and/or long extension cord.

    As for the GFCI tripping, I would check the switchbox and receptacle box first to see if there is any corrosion or condensation. I've seen a fair number that get moisture in them particularly where the cable enters (I know you have conduit not UF - still good to check those boxes).

    If the GFCI breaker has held fine for a year, it isnt the distance that's now causing issues.

    eta: if you want to be completely prepared, bring a new switch, receptacle (regular and GFCI), breakers (regular and GFCI) and enough #12 or even #10 to rewire from the panel to the motor, new boxes, new in-use/outdoor covers, conduit fittings, silicone, DB/wet location wirenuts... basically everything but the buried conduit.
    Last edited by JFletcher; 07-16-17 at 06:48 PM.
    Electricians do it until it Hertz!

  3. #3
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    The closer that you can locate the GFCI protection (by code) to where it will be used, the better. As previous post said, if it worked for a year, then the distance should not be the problem.

  4. #4
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    Distance? No. Could be anything up to an overload if the pump runs for 10 minutes.
    Tom
    TBLO

  5. #5
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    I'm fairly certain the damaged cord was a problem, but now that he has a new motor that should have cured that.
    Now who knows, he could have had the valves closed or something when he changed the pump motor.
    I just want to have everything I can think of with me when I get to go due to how far he is from me. It's over an hours drive from where I'm at or to anywhere that sells supplies.
    If you aim at nothing, you will hit it every time!

  6. #6
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    I would install a new GFCI receptacle at the pump location and change the breaker to a regular (non-GFCI). For me this will eliminate two possible things that may be wrong. Bad GFCI breaker and bad wiring in the conduit under ground.

    If the GFCI receptacle at the pump trips then you know it is not over load, it is not the wiring that you have installed (well it could be), and you know it is not a GFCI breaker. So now all the problem points towards the wiring of the pump or the pump itself.
    Edward
    The only thing I know, is the progressive discovery of my ignorance


  7. #7
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    Bring a Megger tester, since a ground faulted feeder may eventually electrocute everybody.

    Besides, if underground conduit is 12" deep, rather than 18", the GFCI breaker is required to protect the feeder at 12" burial depth.

    Bring a Surge-Suppressor outlet, with EMI filter, to replace the pump receptacle, not a GFCI outlet.
    Roger Ramjet NoFixNoPay

  8. #8
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    The conduit could be filled with water after a year; pretty common via condensation. That water will increase the capacitance between the circuit conductors. If the capacitance gets high enough - and at 100' of run it might - the GFCI breaker can read that as a ground fault and trip.

    If you can (burial depth, etc...), replacing the GFCI breaker with a GFCI receptacle would eliminate that as an issue.


    SceneryDriver

  9. #9
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    Quote Originally Posted by SceneryDriver View Post
    The conduit could be filled with water after a year; pretty common via condensation. That water will increase the capacitance between the circuit conductors. If the capacitance gets high enough - and at 100' of run it might - the GFCI breaker can read that as a ground fault and trip.

    If you can (burial depth, etc...), replacing the GFCI breaker with a GFCI receptacle would eliminate that as an issue.


    SceneryDriver
    If use of a temporary extension cord (with GFCI protection) doesn't trip it then that additional capacitance is very likely the culprit.

  10. #10
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    Quote Originally Posted by SceneryDriver View Post
    ...If the capacitance gets high enough - and at 100' of run it might - the GFCI breaker can read that as a ground fault and trip....
    You got me there. Can we check capacitance at the receptacle with a volt meter, or HVAC meter capacitance function?
    Roger Ramjet NoFixNoPay

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