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Copper wire conductivity vs stainless steel and titanium (grounding a koi pond)

Copper wire conductivity vs stainless steel and titanium (grounding a koi pond)

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  #1  
Old 07-15-13, 06:58 PM
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Copper wire conductivity vs stainless steel and titanium (grounding a koi pond)

I'm new to this site but have some very pressing questions that I hope someone may be able to answer with detailed accuracy. I am having to ground a 2000 gal koi pond due to stray voltage issues. The problem that we are dealing with is that normally 8 gauge copper wire is used for the attachment to the grounding rod. We have a submersible Savio 2050 pump that is 2.3-3.0 amps,240-350 watts and 115 volts. We have tested the voltage from the water when this is on and we are gettting anywhere from 7-10 volts and my husband has been shocked several times b/c of this. To answer some questions that will probably be asked, we have already had an electrician check things in regards to our home and everything passed with flying colors as well as our power company and nothing. I have also contacted Savio Eng in regards to their pump. The water reads a voltage of 0 before the pump is turned on then we see the numbers I mentioned previously. We did a test grounding of the submersible pump with copper and detected no voltage from the water while it was running. This is great news but this brings me to our next problem! Copper is very toxic to koi and other fish so we can't use this. I was told by a koi expert that we could safely use stainless steel or titanium wiring instead of copper. Problem is that the conductivity is pretty poor as compared to copper. Now my question! Is there a way to meet the copper conductivity when using stainless steel or titanium? Do I get a larger gauge of stainless steel or titanium to increase the conductivity? HELP!!! We are about 3 grand sunk into this pond and can't even enjoy it.
 
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  #2  
Old 07-15-13, 07:04 PM
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Is there a way to add a bond lug on the underside of the pond?
 
  #3  
Old 07-15-13, 07:12 PM
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It's inground 2000 gal at 5 ft depth with a firestone liner so I'm doubting it.
 
  #4  
Old 07-15-13, 07:19 PM
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I'm guessing that your pump is not connected to a GFI circuit or receptacle.

How are you "measuring the water" ?

It certainly sounds like your pump is at issue. Have you considered a non submersible pump ?
Keep all electric out of the pond.
 
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Old 07-15-13, 07:33 PM
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Use aluminum wire to bond the pump motor.

I agree with PJmax, I would think a GFCI receptacle would trip for that amount of current leakage.

You might also want to Google "pool water bonding kit"
 
  #6  
Old 07-15-13, 07:54 PM
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It is plugged into a GFI receptacle and it doesn't trip with this going on. Electrician checked the outlet and it trips properly. Voltage being measured by a Multi-meter. Our electrician checked ours compared to his and our meters were spot on with there readings. Our power company also sent their Engineers out and they were getting the same thing on their meters as well. We were told by our electrician that GFI's tripping are based on current flow. There is no current flow from the water just the voltage that's is why it's not tripping the GFI. I believe aluminum may still not be safe for the Koi. I will call the Koi expert I talked to but he only gave the titanium and stainless steel as safe.
 
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Old 07-15-13, 08:24 PM
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we are gettting anywhere from 7-10 volts and my husband has been shocked several times b/c of this
I'm at a loss here. If you can feel the voltage from the pump in the pond......then it MUST trigger the GFI. Your body is feeling the presence of voltage to ground. That's the whole principal of a GFI system.

Having to ground a pump because it has a voltage leak does not make any sense to me.

What I meant before about measuring the voltage......I didn't mean with what.... I meant how ?

Did they put a ground rod in the ground and check from the pump to the ground rod. Or did they just stick the probe in the water and read the meter ?
 
  #8  
Old 07-16-13, 07:50 AM
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It sounds to me more like an issue of the ground and neutral not being isolated at the pond. If the neutral and ground are connected ANYWHERE after the main service disconnect at the house, you are getting a greater potential to the pond than back to the house ground. I've seen this before with inground swimming pools when the pump was turned on, getting a shock near the water cooled light.
 
  #9  
Old 07-16-13, 09:30 AM
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Titanium for grounding?? You must be quite wealthy. Where would you even buy such a thing??

FYI, if my memory serves me, the absolute best metal conductor of electricity is silver.
 
  #10  
Old 07-16-13, 10:17 AM
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I see no reason that a functioning pump should be leaking voltage into the water. It just sounds like an issue that if it gets worse, could become significantly worse for the fish or anyone else who might touch the water.
Have you contacted the manufacturer of the pump?

I do recall seeing a grounding probe used for aquariums. I believe it's intended for tiny little bits of stray voltage that a person would never feel but may affect the fish. Never used one... but it answers the question about what you're looking for.

Aquarium Safety: Ultra-Ground Titanium Probe
 
  #11  
Old 07-16-13, 11:29 AM
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Do I get a larger gauge of stainless steel or titanium to increase the conductivity?
Yes, a larger guage will increase conductivity. You can use a split bolt to splice to copper once it leaves the water.

Aluminum forms an invisible oxide layer which would insulate it from the water. Though it is probably harmless to fish. You would have to take extraordinary measures to keep an AL connection from failing under water. Like using anti-oxidant paste and a potting compound like the one used in pool light niches.

A normal 8 foot ground rod has lousy conductivity. It is only good for high energy events like lightning strikes.

I agree with PJmax and Zorfdt, replace the pump. Even if it's another submersible. It sounds like the least expensive way to rule out the most likely culprit.
 
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Old 07-16-13, 11:39 AM
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And if you replace the pump do not use a pump from the same manufacturer just a case it is an endemic flaw with pumps from that manufacturer.
 
  #13  
Old 07-16-13, 12:41 PM
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I would use stainless steel wire to ground the pump housing. Even though it does not conduct as well as copper it does conduct 100x better than water and would provide a safe path for any stray current. I'd securely clamp it to the pump housing with several hose clamps to insure the wire has good contact with the motor's housing. Or, see if you can find someone with a tig welder that can weld the wire to the pump's housing.

I have seen some odd stray current issues. I've ruled out all other possibilities but assume the stray current is being induced somehow. Similar to how a cordless tothbrush can charge without any physical metal to metal contact.

I have removed the pumps and lights from my koi pond. I switched to a rotary vane compressor outside the pond with air line running to the pond. As a side benefit the motor and pump are now on dry land where they are easy to access.
 
  #14  
Old 07-16-13, 03:35 PM
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Maybe I missed it but I did not see how and where this voltage was measured. One thought that came to me is that the OP is using a digital voltmeter and MAYBE the battery in that meter is shot and therefore giving erroneous readings.
 
  #15  
Old 07-17-13, 05:16 PM
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Is this a pump that is grounded thru the power cord? Or, is it double insulated? Why not ground the pump thru the green wire? I must be missing something. If it is already circuit grounded, there is another issue here.
If you ground a leaky pump with the stainless wire, then you have the risk of tripping the GFCI. Yeah, stainless is 42x the resistance of Copper, but your current is too low to matter.
 
  #16  
Old 07-17-13, 06:06 PM
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FYI, if my memory serves me, the absolute best metal conductor of electricity is silver.
It's gold .
 
  #17  
Old 07-17-13, 06:22 PM
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Nope, it's silver. Silver, copper and a not very close third is gold. Gold does have the benefit of not corroding which is why it's often used to coat electrical connections. And, it's pretty.
 
  #18  
Old 07-23-13, 07:35 PM
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Similar to how a cordless tothbrush can charge without any physical metal to metal contact.

Read more: http://www.doityourself.com/forum/el...#ixzz2ZvRd9nRV
Good call!! A 300-400 watt pump is a fairly significant turbine, I wonder if the EMF generated is enough to charge the water a bit?!?

This would possibly explain the GFCI not tripping too... I'm sure the fish dont mind the charge as they are at the same potential, I think the only one who notices is whomever becomes the pond's grounding path (your husband)!

Titanium (not stainless steel) is the way to go as you will be sinking some steady amount of current I'd be concerned about galvanic reactions at your splice points
 
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