My tank is a death trap.

[rygh]

It is not the first time I have heard people say things about voltage being "inducted" into the water from equipment,
and it is based on some facts, so I do understand why this gets repeated.
If you are bored, here is a fun explanation of why that does not happen.

The theory:
A motor has basically half of a transformer, since it produces magnetic fields to drive the rotor. (true)
Salt water is polar and conductive, so it can be affected by a magnetic field. (true)
So the theory is that it acts like a transformer, and the field from the motor can cause voltages and currents in the aquarium.

In a transformer, an alternating current on the left sets up a moving magnetic field on the winding, which in turn
induces an alternating current on the coil on the right.
In the picture, the left side would be the motor windings. The right is salt water instead of wire.

Problem 1:
As above, the current is generated on the right.
If you connect the bottom-right wire to earth ground, then you indeed get a nice voltage on the top-right wire.
But in the aquarium, the top and bottom are essentially in the same place. There is no wire. It is not tied to ground.
So the current simply flows back on itself and poof you are done.

Problem 2:
Transformers use wire wound together and an iron core, which is WAY WAY WAY more efficient than sticking a pump
near salt water. So the current is basically zero anyway.

 

[Vincerama2]

Wouldn’t a grounding prove actually cause more problems as it’s providing a path to ground for actual current to flow? The way I see it is that the voltage in the tank vs ground is like if the tanks was on a 40 ft tall platform with ground at zero. As long as you don’t fall off, you are safe. The problem in my casevis that the light housings are grounded so the are like holes in the platform you might accidentally walk into...

But no path to ground means no current flow...

Has anyone else tested there tanks for voltages like this?

And yes i’m Testing AC voltage.

I'll test ground plug versus actual earth ground when I get back from vacationin 2 weeks!



Vince

 

[Vincerama2]

It is not the first time I have heard people say things about voltage being "inducted" into the water from equipment,
and it is based on some facts, so I do understand why this gets repeated.
If you are bored, here is a fun explanation of why that does not happen.

Thanks, I'm just spewing what I found on the internet from people saying there are induced voltages.

V

 

[Vincerama2]

Outlet's in stand's ground plug (via extention cord) to the outdoor water main pipe shows 0.1V. Sticking multimeter probe into actual dirt shows 0, but maybe I stabbed a non conductive worm. I went back inside and tried the ground plug and the cold water pipe in the kitchen and it shows 0.1 V

I think this is called a ground loop?

The next experiment, post vacation is, I will test water vs stand-ground with a pump in the water, then remove the pump to see what the water tests at, then take a bucket of salt water and test it with and without the same pump to see if the numbers add up.

And come to think of it, that would seem the easiest way to test any equipment ... a bucket of water, then put the test subject into it.
Unless the presense of OTHER pumps causes things in this pump.

And another question ... why would voltages be additive? If I put one pumo in the water and it shows me say 2V, and then I add another and it pushes it to 4 volts ... why is that? Why wouldn't the potential always be the highest of any device? Why wouldn't current flow between two "leaky" pieces of equipment?

V

PS. For now when I clean the tank, I'm just going to unplug the lights, which is actually simply removing the path to ground.