Stray votlage

[sweet ride]

tagging along....

..... does anyone have a link on how to check stray voltage in the aquarium?

[mike31154]

Most folks simply use a multimeter set to the AC volt scale. One test probe into the water, the other to your ground connection. The voltage potential you get will vary depending on the type of equipment you use and in what shape it is. Any kind of fluorescent lights will most certainly induce some voltage potential into the water, depending on how far above the surface the lamps are mounted. Low levels of AC voltage are generally nothing to be concerned about. However, when the potential gets to a certain point, current will flow through whatever it can, the path of least resistance. If you don't have a grounding probe, the potential is just that, potential only until a path to a lower potential is found or introduced. That could be you, a grounding probe or any number of other things.

If you take lightning as an example, that's a massive, instant current flow through the air, sometimes from cloud to cloud and sometimes from the sky to earth. The voltage potential in a cloud or certain area of the sky is always present, essentially harmless. One of two things will generally cause the lightning to occur. Either voltage potential difference between sky and earth becomes so high that it overcomes the resistance of the air, crack. Or the air gap resistance is lowered somehow, rain maybe, so the current can flow more easily, crack.

So if you're standing barefoot on a wet floor or your skin is wet, chances are you will provide a path of lower resistance for any voltage potential in your tank. You may also get tingled as I have, by touching a flourescent T5 reflector with your arm while your hand is in the water. I've now grounded all my retrofit T5 single reflectors to minimize any difference in voltage potential between them and the water. So theoretically if the reflectors are grounded and the water is grounded, I shouldn't get zapped. But there are a couple of heaters and a powerhead in the water too. If they're breaking down, I could still get buzzed. Hopefully my GFCI devices will cut power to those items before there's a chance of serious injury.

[sweet ride]

Originally Posted by mike31154

Most folks simply use a multimeter set to the AC volt scale. One test probe into the water, the other to your ground connection. The voltage potential you get will vary depending on the type of equipment you use and in what shape it is. Any kind of fluorescent lights will most certainly induce some voltage potential into the water, depending on how far above the surface the lamps are mounted. Low levels of AC voltage are generally nothing to be concerned about.

what value should someone be looking for "as a low value" safe value?

[Binare]

How did you test your ground probe?

[mike31154]

Originally Posted by sweet ride

what value should someone be looking for "as a low value" safe value?

That's a bit of a 'loaded' question. It can vary depending on the person potentially getting zapped too. Don't want to open myself up for any lawsuits here by putting up numbers. Let's just say if you're getting readings higher than about 20 volts AC, you might wish to investigate to see if there's a component starting to break down in your system.