Well Pump Puzzle

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pk04607

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I hope someone has an answer for this. I had a customer call with a high copper content in his water test. There are blue-green stains in his sinks. He said he never had this problem until the well pump was changed a few years ago and it has gotten progressively worse. The pump is a 110vlt. deep well, (160'). The grounding conductor FROM the pump was bonded to the steel well casing but not brought back to the panel. The service is a 100 Amp single phase 2 wire service lateral with grounding electrodes at the meter and none at the service panel about 75' away. The meter is on the utilities pole with the transformer. I amp probed the utility grounding electrode conductor and the hot conductor to the pump at the same time. When the pump comes on the utility grounding electrode conductor shows 3 amps current flow. We did this several times. This indicates a fault in the pump or wiring in the well casing to me so I ran a #6 bare copper from the well casing to the panel ( about 10 ft.) expecting the breaker to trip when the we ran the pump again. This is where I'm stumped. The utility grounding electrode conductor still showed the 3 amps but the #6 to the panel nothing and yes the main bonding jumper is in the panel. Any help would be appreciated. Thanks, Pat.
 
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This is pretty textbook.

You have a loose utility neutral at some point. (IF this is indeed a 110V pump. That's an odd pump voltage for 160 feet deep)
 
I think Marc hit it. That will cause the current on the gec. But, the copper loss problem is probably caused by a ph problem and the water needs treatment to keep the pipes from developing pinholes. This has been discussed here before.
 
If I was troubleshooting this, I'd get my Beast of Burden tool (or, alternately, a couple of hair dryers) and put a load on the phases one at a time in the panel and amprobe the GEC.
 
Hi Marc, It is odd to have 110 vlt. motor on a deep well pump, but it is. His house is set up for 110vlt because he has a large battery back up system for his ham radio. The utility grounding electrode conductor is only showing current flow when the pump runs. Seems if he had a bad nuetral on the utility side the lights would act up and the utility grounding electrode would be seeing more current flow. Thanks for your reply, Pat.
 
Hi Marc, I usually find a bad utility or se nuetral connection with the cloths dryer but this place is set up for 110. I'll look into the archived posts for the pitting pipes causing the high copper. It could be coincidence that it happened around the time the pump got changed to 110 vlt. for the inverter system. I still don't see why the #6 would't see current flow before the utility ground would, but I think he should try changing the pump incase it's bleeding off to the utility ground or do you think we should have the utility go over their connections first. Thanks, Pat.
 
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pk04607 said:
Hi Marc, I usually find the bad nuetral with the cloths dryer but this place is set up for 110. Pat.
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I certainly don't intend to de-rail your original matter with the finer points of loose netural troubleshooting, but... the only thing in most electric clothes dryers that operates on 120 is the light and the motor. Both are light loads. The heating element is 240, and does not utilize the neutral. A microwave oven or a hair dryer would be a better choice. The Best of Burden tool is the best, because it is designed especially for loose neutral (and loose hot) troubleshooting. Knowing for sure now that this well pump is 120V makes me feel even better about my loose utility neutral diagnosis.
 
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PK, Is this house supplied with a 120 volt service or a 120/240 volt service? You say it's set up for 110 volts.
 
yanici said:
PK, Is this house supplied with a 120 volt service or a 120/240 volt service? You say it's set up for 110 volts.
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A 110 volt service is unusual, but not unheard of. It's usually the first step before going "off the grid". Getting your inverters system set up for 110 volt AC from your battery bank is much more economic than getting an inverter to make 120 and 240 with the legs being 180 degrees out of phase. I think I've only seen 2 or 3 modern 110 volt services. I've seen quite a few old one's still hanging on from the 1930's.
 
pk04607 said:
but I think he should try changing the pump incase it's bleeding off to the utility ground.
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No, I believe that would be the wrong move at this point, as it is still a guess on your part. Doing a megger check of the pump and associated wiring down the well (between hot and ground and between neutral and ground) would prove that out in a minute or two.

pk04607 said:
...or do you think we should have the utility go over their connections first. Thanks, Pat.
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That would be my next move.
 
Pump Circuit Neutral?

Pump Circuit Neutral?

Have you compared the current in the ungrounded conductor to the pump with the current in the grounded (hot) conductor to the pump?

Put your clamp-on ammeter around both the hot and the neutral. If you get a net current, then there is a leak to ground big enough to measure.

If may be that you have a problem with the neutral to the pump.

Try running the pump through a GFCI. If the GFCI trips, then fix that problem first and see if it solves the other one.

If you have an open neutral in the pump circuit, and the neutral is shorted to ground at the pump, you could be running the pump through the well casing.
 
Hi Mark, I checked the pump to ground and didn't read anything, but I have seen that before and the pump wouldn't act up until it was under load. I think I'll try loading up the nuetral, maybe I can see some break down if it's a bad connection causing that current flow. I hate to bother the utility without something solid and I don't want to put the customer through any expense if it's not the pump.The service is 110 vlt. for the inverter. Thanks, Pat.
 
Hi Bob, I'll check the amps on the ungrounded and neutral conductors for a difference. Thanks, I didn't think to do that. If it was running through the well casing I should have gotten an amp reading on the #6 back to the panel. I think GFCI's are too sensative for me to check a well pump with though. They can trip with refrigeration equipment when it's working fine with just a little case leakage. Thanks for your input. Pat.
 
Hi Mark, I just read your post about the cloths dryer and your right there are better choices to break down the nuetral connection. I've always tried the dryer because it's always pulled through for me. Maybe I just got lucky each time with the motor start. I've seen several and they always shifted the voltage. I will keep that in mind though. Thanks, Pat.
 
pk04607 said:
Hi Mark, I checked the pump to ground and didn't read anything, but I have seen that before and the pump wouldn't act up until it was under load. .
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Yeah, that's why you really need to do that check with a megger and not an ordinary ohm meter. A megger will make those tiny faults really obvious.
 
Hi Mark, Thanks for the input. I'm going to try breaking that nuetral down first. Then I'll dust off the megger. Thanks again, Pat.
 
160' deep well...submerged pump...brings back bad memories.
I lived with well water all of my life until about 7 years ago. Finally got "city water" on my road. Didn't take me long to hook-up. My dad's well was only 50' deep and he used a above ground "jet" pump. My well is 120' deep which required a submerged pump. IMO...the problem that you're having is most likely caused by bare spots in the wiring insulation on the pump conductors. As the pump starts, there is a twisting motion which can cause the wiring to be rubbed against the well casing. This will eventually wear away the conductor insulation. There are many mixes of current flow that can occur between the hot lead (120V pump) and the grounded (neutral) and grounding conductor (if the pump is grounded). Which wire(s) is exposed, it's position in the well (how deep), the distance between any exposed areas and the chemical composition of the water (Ph, dissolved solids, etc.) will all play a part.
The fact that batteries (DC current) are involved in this equation rings a bell. It may be that you have current leakage from the battery bank, thru the pump leads and into the well casing/earth. This can cause galvanic corrosion of the conductors themselves, the well casing or the pump piping (if metal).
This is my theory, and it may be full of holes (no pun intended).
Long story short...probably a exposed conductor in the well wiring, or the insulation in the pump is at fault.
If the pump has to be pulled, I recommend installing a "torque arrestor" on the piping just above the pump. Also, you can buy spacers that mount at intervals on the pump piping to support the pump cable and keep it from rubbing the casing.
Just a thought
steve
 
Hi Steve, I asked the home owner if torque arrestors were on there but he didn't see the installation so didn't know. I've seen that in the past where the wire rubbed and the insulation wore off. I've always been able to pick up that and winding leakage or bad splices with my meter. I'm not picking up any amperage on the ground from the casing to the panel either. I think Marc is right the 3 amps on the utility ground is from a bad nuetral connection and the copper in the water is another issue. I told the home owner he should deal with the outfit that installed the inverter and the battery bank to be sure that grounding is right, I don't want to void any warranty. Thanks, Pat.
 
A co-worker of mine had to replace his copper piping at his home twice because he didn't watch his PH. The copper started getting pinholes. He also was on indepenent well water.
 
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