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New Member With A Question

313 Views 3 Replies 2 Participants Last post by  trailscout, 
T
Hi. I am not an electrician. If I understood correctly, new members could join in order to ask questions? Hopefully I won't get booted for not being an actual electrician.

That said, thank you to admin for allowing me to join.

In my search for an answer, I came upon an old thread on this site dating back to 2011. The problem concerned submersible stock water trough heaters. There was a few tenths of a volt between the water and an earth ground. Adding a ground did not reduce the voltage.

The thread went on for 7 pages, some of which I understood and some I was uncertain of. At one point the thought was the ground wire had current on it. The thread starter tried a 3/2 plug and the current to ground disappeared. The device has a thermostat on it and I'm not sure he checked to see that the heater was on when he tried the 3/2 plug.

At any rate, when I tried a 3/2 plug, the water to earth ground voltage did not disappear.

I then searched for construction of these devices. They are a resistance coil inside a cast aluminum housing with the coil packed with a non conductive powder that does transmit heat.

And now my question: Is it possible that the 1250 watt coil could be inducing eddy currents on the surface that would produce a voltage from the water to earth ground?

Here's a picture of the heater in question.

Edit: I'm in Northern Arizona

Thanks, Harold

Gas Nickel Circle Metal Aluminium
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Discussion Starter · #2 · (Edited)
More perplexing info:

Just went out and did some more testing.

1. Put the heater in a trough that had ice to be certain the thermostat remained on.

2. For chuckles, measured the current from water to ground and from the 3/2 plug tab to ground which of course were the same at 0.2 volts AC.

3. Then turned off the current at the outdoor 20 amp GFI. The water to current voltage disappeared.

4. Removed the 3/2 with the 20 amp GFI breaker still turned off. The water to ground current measured 0.7 volts!

So there's some with the ground plug removed using the 3/2 plug, but considerably more with the ground in play.

So maybe there is (some) eddy current plus some stray current from somewhere getting into the ground?

If any wonders why worry about tenths of a volt, some animals, particularly horses, are very sensitive about voltage and won't drink if there is any at all.

I'm thinking the 0.2 volts will allow the me to drink but not the 0.7 volts. Using the 3/2 they won't be protected if there is a fault in the heating device.

So now I'm wondering if a ground wire in the water to earth ground would protect them if a fault in the device did occur which is not likely.
 
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