Main Klixon breaker on 3/4 hp 3-wire submers. pump keeps tripping

Discussion in 'Electrical Forum discussion & Blog' started by MichaelSK, Jul 23, 2018.

  1. MichaelSK

    MichaelSK Member

    Joined:
    Oct 1, 2016
    Occupation:
    nurse
    Location:
    North Central Florida
    This electrical problem has me perplexed. I thought Valveman, from another forum/thread, solved the problem with a simple straight forward explanation - the Klixon-type breakers become weaker with subsequent "breaks."

    Background: 3 y/o Shakti 3/4 hp 3-wire submersible pump - the control box has two breakers (start and main/run). I have checked amps on several occasions, and they have been nominal - well within specs. (e.g. The Y-line amps ~ 5.4 [6.7/7.37]; B-main amps ~ 5.1 [5.8/6.38]; R-start amps ~ 2.0 [2.6/2.86]) note: the numbers in [ ] are full load/max load specs.

    Based on what Valveman said (makes good sense, appreciated his explanation), I removed the Klixon breaker and installed a 7.5 amp slow-blow fuse. Went through a couple of fuses, apparently there are intermittent load spikes on the "main circuit," which I have not been able to isolate and describe.

    Does anyone have any suggestions how to problem solve this one? I am in the process of accessing two junction boxes to assess the line connections (?condensation, oxidation, intermittent shorting?). Short of purchasing an entire new length of wire to run from the control box, which is located in the main house mechanical room, down to the well head - any other suggestions?

    At this point, I am reluctant to merely short the breaker if indeed there is an unidentified problem.
     
  2. genmaster

    genmaster New Member

    Joined:
    Sep 25, 2017
    Occupation:
    Master Electrician
    Location:
    Pennsylvania
    I'm assuming this is a submersible well pump (240 vac, 2 wire with a ground). When does the fuse/breaker trip? Is it tripping when the pump starts, while it's running, or is it blowing while sitting idle. Before you pull the pump and replace wire, have you done resistance checks on the wire? Check the pump motor winding resistance by reading between the two wires supplying the motor - should be relatively low. Also, check for resistance to ground on those same leads. You should read infinite or at least very high resistance. If the motor and its wiring check good, it could be a bad capacitor or board in your control box, in which case you just replace that - not too expensive or labor intensive.
     
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  4. MichaelSK

    MichaelSK Member

    Joined:
    Oct 1, 2016
    Occupation:
    nurse
    Location:
    North Central Florida
    To make a long story short. I live in north central Florida (lots of lightning storms), the house is 30 years old, and it's a new 3/4 hp 3-wire Shakti pump. The breakers and fuses installed to replace the Klixon breakers kept interrupting, then the relay burned out again.

    I put a megohm meter on and found some anomalous readings associated with wiring in the mechanical room. Pump motor windings and UF-B cable were acceptable. Checked the capacitors - they were ok.

    I dug a hole about 1' deep to locate the house ground rod. It was a 1/2" galvanized rod. The zinc (pot metal) connector had almost completely disintegrated. It was almost unrecognizable. The #6 solid copper (200 amp service) was 1 1/2" from the ground rod, the telephone ground had been connected to the house wire, so the telephone was not grounded either!

    I temporarily reattached the house ground to the ground rod, tore out all the wiring in the mechanical room associated with the pump. The electrician 30 years ago had used 16 gauge primary wire pig tails to wire the pressure switch, on/off switch, and control box to the UF-B cable! The metal box was stuffed full and insulation was cracked/split/abraided.

    I redid the plumbing piping, installed a CSV valve, installed all new and greatly simplified wiring (12 ga) in non metallic watertight conduit. The pumps works reliably so far - have had several thunderstorms. I need to ask some questions about grounding/bonding systems and codes to install a new grounding system.
     
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