CWA - it's trivial to demonstrate your reasoning is fatally wrong.
Proceeed as follows:
1. take one glass of saltwater from your tank.
2. insert into the glass two bare wires connected to the phase and neutral wires on a power outlet through a GFI.
3. turn on the power and observe how the GFI does not trip and how you know current is flowing since the water in the cup will start to boil in around 1 second.
4. turn off the power and now insert a third wire into the cup, this new wire being connected to ground pin - for your own education, connect to the ground of another eletrical outlet (so not passing through the GFI at all).
5. Turn on the power and observe that the GFI trips instantly.
6. Come back here and confirm that you were wrong and thank me for potentially saving your life in the future.
It will only take you five minutes to do this - well worth your effort in my opinion.
And now back to trying to help others realise why a voltmeter isn't helping prove anything
V=IR. Saltwater isn't a great conductor (compared to a copper wire anyway) so you know "R" is quite a big number (measure it if you have to), so with the probes of the meter spaced well apart you would be able to measure a significant "V" if "I" were anything to worry about.
As for not changing the cirucit - moving between having an really high imperance earth (your tank stand is a poor conductor) and low impedance earth, whether coupled through a capacitor or othewise, is a pretty profund change. In terms of magnitude of the change in the circuit it's no different to connecting your tank to the phase wire on an electrical outlet - obviously a rather dumb thing to do and something that everyone here would agree has changed the circuit just a little bit...
The only reason you're getting a measurement at all is because the earth and neutral wire are connected together back at the fuse box (in most countrys) or at worst at the nearest sub-station.
Anyway, every tank should be grounded with a GFI - it doesn't matter why people choose to do this - just so long as they do.
Proceeed as follows:
1. take one glass of saltwater from your tank.
2. insert into the glass two bare wires connected to the phase and neutral wires on a power outlet through a GFI.
3. turn on the power and observe how the GFI does not trip and how you know current is flowing since the water in the cup will start to boil in around 1 second.
4. turn off the power and now insert a third wire into the cup, this new wire being connected to ground pin - for your own education, connect to the ground of another eletrical outlet (so not passing through the GFI at all).
5. Turn on the power and observe that the GFI trips instantly.
6. Come back here and confirm that you were wrong and thank me for potentially saving your life in the future.
It will only take you five minutes to do this - well worth your effort in my opinion.
And now back to trying to help others realise why a voltmeter isn't helping prove anything
V=IR. Saltwater isn't a great conductor (compared to a copper wire anyway) so you know "R" is quite a big number (measure it if you have to), so with the probes of the meter spaced well apart you would be able to measure a significant "V" if "I" were anything to worry about.
As for not changing the cirucit - moving between having an really high imperance earth (your tank stand is a poor conductor) and low impedance earth, whether coupled through a capacitor or othewise, is a pretty profund change. In terms of magnitude of the change in the circuit it's no different to connecting your tank to the phase wire on an electrical outlet - obviously a rather dumb thing to do and something that everyone here would agree has changed the circuit just a little bit...
The only reason you're getting a measurement at all is because the earth and neutral wire are connected together back at the fuse box (in most countrys) or at worst at the nearest sub-station.
Anyway, every tank should be grounded with a GFI - it doesn't matter why people choose to do this - just so long as they do.
