I am working on a house that sat vacant for a few years. The pressure tank had a leak on the bottom from rust. So a new tank was installed along with new pressure switch 30/50 and gauge etc. There was only one wire with 2 leads going to switch as opposed to the normal 2 wire 4 leads. This is hooked up to a 15 amp breaker than to a coil of some type and a definite purpose contactor. The issue is the pump only runs 30 seconds or so and trips the breaker ? The well pump is submersible type but unknown hp or depth. But I would guess under 100 ft since neighbor says his is 75ft. Any suggestions as to why breaker is tripping would be greatly appreciated. thanks

  • The single wire switch is ok but anything that needs to be done on the pump or pressure switch the breaker will need to be turned off because there will be 120v on the non switched hot and that will feed through the motor and can be a hazard. I would replace with a double pole motor rated switch. I would use the wire size as a guide for the switch amperage since we do not know the size motor in the pump. There are 2 reasons to replace the switch 1 safety and 2 voltage drop , high resistance in the switch will create starting problems. The coil and contactor may be a run dry safety circuit. – Ed Beal Jul 19 '18 at 16:59
  • Thanks for the reply. Yes I understand to shut off the power before doing any work. I actually shut off the main breaker before doing any work and use tester to be sure. This is the way it has worked since being built (not by me) in 1978. I was suspecting the definite purpose contactor was possibly stuck in the closed position from lack of use. The old pressure switch on the tank had corrosion on it as well so it was replaced with a new one. Would a stuck contactor cause the breaker to trip? – Scott Jul 19 '18 at 18:00
  • Is the breaker GFCi or AFCI? – Harper - Reinstate Monica Jul 19 '18 at 18:07
  • Item # 71801 Model # QO115CP Square D Qo 15-Amp 1-Pole Standard Trip Circuit Breaker – Scott Jul 19 '18 at 18:16
  • I would not expect a contactor to be the cause of the problem, many well controls have safetys that shut the pump down when the load is two low (water level below the pump). At this point I would guess the pump is not getting to speed this causes it to draw locked rotor current if stalled and maybe a bit less, I would try to start it a few more times about 30 minutes apart and see if it will start or if it takes longer between attempts like going from 30 seconds to a minute, then keep trying it may run if after 3 or 4 times is is tripping the breaker you are looking at a new pump. – Ed Beal Jul 19 '18 at 19:38

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