Voltage from pond with pumps off

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Any help greatly appreciated. 12000 ltr pond with gold fish. With pond pumps running (1 for filter plus UV, 2 for features) I'm getting a stray voltage of between 0.7 and 5volts from the pond surface. If plugs remain In socket but turned off, I still get the same but varies a lot between those value. I'm presuming that this is mainly coming from the earth some how. RCDs protect everything and all plugs are earthed but not enough current to activate RCDs. Pumps are in good condition and it even happens with a brand new pump. Totally confused.
 

mrsclem

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I would try pulling each pump and see if you still get the current. You can also try plugging the pumps into another outlet and see if you still have the problem. It has to be coming from some electrical element. Do you have anything else in the pond? lights, air pumps?
 
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Thanks for response. I have checked all pumps separately on and off (issue remains) tried them individually (1 plugged in at a time on and off) plus unplugged . Also through different RCDs in different outlets, 1 direct from the house. No lights or air pumps at this stage. Consensus at the moment is a fault in the house somewhere, introducing voltage into the earth. Maybe short between neutral and earth. How that gets into the pond via a pump with no fault is beyond me though.
 

j.w

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No clue on electricity issues, sorry.
 
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Stray current and water do not mix. I would find good electrician or start taking out one electronic at a time and see if you find the culpret.
 
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It is possible to get stay current from the earth into a body of water like a pool or pond. Figuring out WHY and then what to do about it can be quite an undertaking.

A few thoughts/questions:

1. When and why did you start measuring this? Is it possible it’s been there all along and you just never noticed until now?

2. What is making you think the current is entering through a deenergized pump? You said you tested all of them separately energized and deenergized and the current was always there. At least that’s how I understood your comments.
 
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It is possible to get stay current from the earth into a body of water like a pool or pond. Figuring out WHY and then what to do about it can be quite an undertaking.

A few thoughts/questions:

1. When and why did you start measuring this? Is it possible it’s been there all along and you just never noticed until now?

2. What is making you think the current is entering through a deenergized pump? You said you tested all of them separately energized and deenergized and the current was always there. At least that’s how I understood your comments.
Found by chance. I had a cut on my thumb whilst adding a plant to the pond. Together with a wet knee earthed myself and felt what I originally thought was a bee sting. Repeated shocks proved it was something else. Can't feel current unless you have a cut on your hand thats in water, so must make it extra sensative. (Thought static initially) tested with multimeter and found voltage. Started turning off pumps without unplugging but some voltage still remained. Only when all plugs are physically removed does voltage disappear. Which led me to believe its not an induction issue and as sockets were turned off Earth or possibly (Earth/Neutral) must be the culprit. This is a new pond with old and new pumps. It's possible this has been an issue before in old pond but not noticed.
 
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Stray current and water do not mix. I would find good electrician or start taking out one electronic at a time and see if you find the culpret.
Electrician coming over today to start isolating items in the house and testing Earth for stray voltage.
 
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Found by chance. I had a cut on my thumb whilst adding a plant to the pond. Together with a wet knee earthed myself and felt what I originally thought was a bee sting. Repeated shocks proved it was something else. Can't feel current unless you have a cut on your hand thats in water, so must make it extra sensative. (Thought static initially) tested with multimeter and found voltage. Started turning off pumps without unplugging but some voltage still remained. Only when all plugs are physically removed does voltage disappear. Which led me to believe its not an induction issue and as sockets were turned off Earth or possibly (Earth/Neutral) must be the culprit. This is a new pond with old and new pumps. It's possible this has been an issue before in old pond but not noticed.
Was also wondering about how voltage from the earth could get into water through pumps if they are isolated in pond. Do pond pumps have an earth to the water? (Probably a very stupid question) If not, I can only presume that all pumps are faulty with a neutral or earth wire making contact with the water, even the new pumps as logically a circuit must be made for power to reach the water.
 
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Update: Firstly we have a bad earth from the house, this is causing "controlled" stray voltage to follow the course of least resistance which is the pond. We also get a smaller voltage from a smaller pond. Most households have controlled voltage from computer equipment or smart devices, even cookers. This voltage would normally follow the correct earth route through the spike in the ground near the consumer unit, but as our wiring to the spike appears faulty this is creating resistance and creating backflow to all earth points throughout the house. The pond just happens to get the worst of it due to the body of water creating a more favourable earth.

We have an electrician fixing the earth asap but obviously keeping an eye on the surge voltage protection for personal safety until it's fixed. The surge protection in house will also protect the fish in the pond but is a one time deal and needs replacing if it kicks in.

To get over the problem with backflow to the pond so I can get the filters running again we will be putting a new earth spike near our shed and wiring our sockets from that. Live and neutral will come direct from the house. I'll then test to make sure the situation isn't being made any worse by picking up other localised voltages but I should get a zero reading before activating main pump. Anything else will be inductive charge which we can't avoid unless we use external pumps.

Once the bad earth is sorted, either by adding a secondary linked spike and or replacing the earth wire to the existing spike, we'll check from backflow again and take it from there.

Hope this helps anyone else getting a similar problem :)
 
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If your having a hard time getting ground. Running length of counterpoise may be a cheap solution it will take your limited reading and disburse of a wider area. If you have limited space than a ground well will do the trick
 
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If your having a hard time getting ground. Running length of counterpoise may be a cheap solution it will take your limited reading and disburse of a wider area. If you have limited space than a ground well will do the trick
New Ground Rod hammered in to near ground level near shed and I installed all new electrics taking live and neutral from house and earth from the new rod, Earth tested several times to be sure and hey presto. Down to 0.09Vs it's been a long day but well worth it. House Earth still not fixed so we are at more risk than the fish. For reference house voltage through earth is between 0.7v and 2v depending on whats on and running.
 
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I work in the power industry we have fun occasionally finding proper ground particularly when we are in an area with next to no soil. And it is "ledge " solid rock " bed rock " much the same issue your having but could be a number of causes
 

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