Well Pump breaker tripping. No noticeable pattern.

[Average_Individual]

About 2 weeks ago the circuit breaker for my well pump tripped. The breaker was turned back on and worked fine until about 4:30AM when I turned on the sink and it came to a drizzle. I have been trying to figure out what it was but there isn't an easily noticeable pattern to when it happens. Occasionally it is 6AM, sometimes it is 6PM.

I don't know what the pumps information is, all I can say is it is on a 15amp breaker, so I assume it is a 1/2 HP. I checked the amperage and it was around 12.2 - 12.5. In addition to that I also checked the resistance which seems rather low to me. It was between. 1.5 and 1.9 Ohms. I figure this means there is a short circuit somewhere. I mean the well is approximately 100 ft deep so if it is 12 or 14 awg wire then that's going to be about .15 to .25 Ohms of resistance by itself. But, the pump is probably about 20 years old, and I noticed that it is short cycling a bit. coming on at 30psi and turning off at 45psi rather than 50. Also, the pump is a 2 wire pump.

I checked the filter and it still looked good, And all the pressure tank, switch, and softener were replaced in 2020

Just thought I would post to see other peoples thoughts on the matter. Any help appreciated. Thanks.

 

[Fitter30]

Ohming out a two wire pump it has the starting components built into the pump. Ohm readings probably don't mean to much. Short cycling look at the expansion tank. Drain the system down measure the air charge with a 50 lb tire gauge. Should be couple of lbs less that the turn on pressure. If water comes out tank is bad or if you try to adjust air charge recheck pressure after 20 minutes if it loses pressure its bad. Bike tire pump with pump it up if using a air compressor short bursts measure pressure after each burst or else the bladder could fail. Most switxhes adjust the same

https://www.google.com/url?q=https://www.pentair.com/content/dam/extranet/web/nam/parts2o/manuals/adjusting-well-pump-pressure-switches-instructions.pdf&sa=U&ved=2ahUKEwju1-DP9dGPAxXQtIkEHbFvEBMQFnoECAgQAw&usg=AOvVaw3pdEvmhPQimUvPoRhIwBfQ

 

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[Reach4]

2-pole breaker, indicating a 230V pump?

A 1/2 hp 115 volt pump motor winding is about 1 to 1.3 ohms but would have a bigger breaker amps.
1 HP 230 volt is about 2.2 to 2.7 ohms.

With the breaker off, measure resistance from one of the power wires to ground. Should be over 1 meg, but 100Kohms is not that bad.

Ideally you would measure with a special high voltage ohmmeter called a megger, but few have one of those.

 

[Average_Individual]

2-pole breaker, indicating a 230V pump?

A 1/2 hp 115 volt pump motor winding is about 1 to 1.3 ohms but would have a bigger breaker amps.
1 HP 230 volt is about 2.2 to 2.7 ohms.

With the breaker off, measure resistance from one of the power wires to ground. Should be over 1 meg, but 100Kohms is not that bad.

Ideally you would measure with a special high voltage ohmmeter called a megger, but few have one of those.

Yeah, sorry. When I measured the voltage it was about 120v and the breaker is a 15A Single pole breaker. Do you mean measure from the pumps wires to ground or from the supply/ breaker wires to ground? Thanks.

 

[Reach4]

A 1/2 hp 115v pump would normally be powered thru a 30 amp breaker. 12 amps would be consistent with a 1/2 hp 115v pump pumping a lot of water somewhere.

As a confirmation, confirm that the white wire going to the pump measures fairly zero volts to a ground (like a green wire etc).

Short cycling is consistent with a failing pressure tank.

As to the 15 psi difference between cut-in and cut-out pressures, how about a photo that shows the pressure switch,pressure gauge, input to the pressure tank, and the pipe coming from the well, including any gadget, such as a check valve, in that path.