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Thread: waterfall in pond GFCI ???

  1. #1
    Join Date
    Apr 2005
    Posts
    21

    waterfall in pond GFCI ???

    Sorry this is going to be a long one guys. I just can't figure this out, I desperately need your ideas. Last year I wired up a pump for a waterfall in a pond. Just a little residential one, in a customers backyard. It ran fine for about 7 months. It is about 100 feet from the house panel. I buried I believe 3/4 or 1 inch pvc. One hot, one neutral, one ground. I up'd the thhn to number 10 guage. Went from a breaker in the panel to a gfci which fed another plug right next to it in a four square weather box with a weather proof cover. The kind that you can keep plugged in all the time. He runs this pump 24 7. Well the gfci tripped in February. He called us this spring about a month ago. I went out there and couldn't get it to work. Took off the gfci and put just a reg. duplex on it and it tripped the breaker in the house. Ran a cord from the house and it again tripped the breaker in the panel. I finally figured out it was the pump. Manufacturer said ya we had a bad batch. So we installed a new pump from a different manufacturer. Plugged it into the circuit and ran it with no Gfci. It ran for two days straight. Cool I went back out there put the new gfci from before back in and all was well. Well a week later it trips the Gfci again. I go out today with digital apm probe in hand. With everything on including low volt lights it only draws 9 amps amps. I have 20 amps ran out there and 123 volts reading on my digital tester. So I put a brand new 20 amp GFCI in and after about 2 minutes it trips. No spike in amps on the tester. So I go to home depot and get a GFCI 20 breaker. Install it and make the 2 plugs regular duplexes no Gfci outside now just inside in the panel, turn it on clean up pack up still running everythings great. Nope tonight I get a call and its tripping the GFCI breaker now. I am totally lost on what else to do. The only thing I haven't done is replace the thhn 10 in the pipe. I don't think I need too though because just the GFCI was tripping and not the breaker. I believe a pump for a pool can not be on a GFCI as long as it is a single plug at a lock in type plug. Is it true for pumps for ponds. I getting the code book out right now. just thought I would see what you guys think might be happening. What are the chances of 2 pumps from 2 different manufacturers being bad. Please help

  2. #2
    Join Date
    Dec 2004
    Location
    Fort Collins, CO NEC: 2011
    Posts
    15,320

    Re: waterfall in pond GFCI ???

    You'll save time if you whip that meter out sooner.

    Put the GFI closer to the pond, if practicable, because distances freak them out due to the...something that iwire sounded a lot more intelligent saying.

    Did you use THHN or THWN?

  3. #3
    Join Date
    Feb 2003
    Location
    Indianapolis
    Posts
    6,102

    Re: waterfall in pond GFCI ???

    I gotta agree with George on this one. Put the GFCI at the location where it will be used. Also, the wire should be THWN not THHN. You might be getting a little leakage if the insulation was damaged at all when it was pulled in. THHW and THWN are both listed for wet locations but THHN is not listed for a wet location. Your conduit run is a wet location.
    Charlie Eldridge, Indianapolis, Utility Power Guy
    Responses based on the 2011 NEC, unless stated otherwise.

  4. #4
    Join Date
    Apr 2003
    Location
    Westchester County, New York
    Posts
    3,552

    Re: waterfall in pond GFCI ???

    Most conductors today are dual rated for THHN/THWN.
    If your GFCI protection is not located close to the pump, you may have enough current leakage along the conductors that will make the 5 milliamp setting of the GFCI close to the tripping level.

    Also you may have damaged the conductors as they were pulled, and now as time has had it's toll on them and maybe some moisture has entered the PVC, you have a high resistance short that takes more time to trip due to the time current value of the breaker. You may need to replace those conductors- a megger test may help to determine that.

    Good luck and keep us informed.

  5. #5
    Join Date
    Aug 2004
    Posts
    10,927

    Re: waterfall in pond GFCI ???

    My guess is you may have scuffed the insulation on the wires when it was installed and this causes enough leakage to trip the GFI.

    I run across this on VFDs that have built in GFIs now and then. The wirer typically ran the wires a few hundred feet through a relatively small conduit and managed to damage one of them. Usually it shows up on megger test.

    I am inclined to put the GFI out by the pump as well. GFIs are funky things, and it's best to reduce the variables they are working with as much as possible.
    Bob

  6. #6
    Join Date
    Apr 2005
    Posts
    21

    Re: waterfall in pond GFCI ???

    Well I went out there and used my digital multi meter. I checked my ohms, continuity. Everything checked out great. I told him it was the pump again. I think continuity would have been picked up if the wires were bad. We will see. Yes the wire is also thwn.

  7. #7
    Join Date
    Jun 2004
    Posts
    25

    Re: waterfall in pond GFCI ???

    I have a pond with a pump in it at my house and I have the GFCI located close enough to the pond to plug the pump directly into it, with an inuse weatherproof cover installed on it. It works fine. A couple years ago the GFCI started tripping every once in awhile and I replaced the pump and have had no trouble since.

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