DIY - How to test for Stray Voltage in your Aquarium

[sleepydoc]

Not surprising - it simply means there is a potential between the two leads. If you take a digital volt meter and hold the leads in the air, there will frequently be a parasitic voltage of a few millivolts. What is more surprising is that there is a voltage between the leads when they are both in the water. What happens when you touch one lead to ground and the other to the water? That will give you the true voltage of the water. After doing that switch your multimeter to amps and measure the current - it should be something pretty small. I just checked mine just for kicks and there was ~1.69V AC and ~0.68V DC relative to ground. When I checked the current it was 0.09 mA.


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[iSeeMax101]

I spent the better half of the last hour reading this thread. Very informative. I've learned a few things and I found myself lost on a few others. I have a very minor understanding when it comes to electricity, volts, current etc but I can say that this thread has helped to put things into perspective. I'm looking to start school as a Lineman soon so I'll be sure to read this again once I have a little more understanding under my belt.

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[madweazl]

Clear as mud...

 

[madweazl]

Checked mine today and was actually surprised by the results of 0.8v.

 

[Jeremy1988]

Stray voltage of any magnitude is not harmful. Voltage does nothing. It is current that does something, and is what can be potentially dangerous. Without a path to ground, there is no current flow.

The voltage in the tank, can be read with the meter, because a current flows through the meter to ground, due to the voltage potential in the tank. Remove the grounded test probe, you get no reading = no current flow. Current does the work, not the voltage.

Anything under 40VAC, is considered "low voltage," as in most cases the current flow caused by this potential, would be harmless. Getting above 50VAC, as kcress indicates is "high voltage" and the potential for injury or death is present, if that voltage is given a path to ground.

Saltwater, due to its ionic nature, will always show some potential (voltage) between the water and ground. The potential may be too small to measure, or you may read 12VAC, or so. Also, inductive loads (pumps) can impress a voltage in the water--due to the magnetic fields, yet not be damaged or malfunctioning. However, if you are reading something above 40VAC, it is cause for further investigation.

Looks like mine is 27 something and when I turn the heater off it jumps down to 5 or so...maybe replace the heater? Or is that normal, 10 gallon tank btw with hang on back filter

 

[Windy2]

Ground probes are not a safety device and in my opinion should not be used in an aquarium due to increased hazards when grounded. I know this argument will continue until hell freezes over, so here is a suggestion that should satisfy most of you. Put the ground probe on a switch. If there is a short the equipment may fail via the probe, or you the next time you touch the tank. So I recommend, if you have a probe put it on a switch and always disconnect it when you work on the tank.

 

[uncleof6]

Looks like mine is 27 something and when I turn the heater off it jumps down to 5 or so...maybe replace the heater? Or is that normal, 10 gallon tank btw with hang on back filter

Not really enough voltage to be concerned about. A cracked heater will impress ~100+ volts. A very obvious problem. A heater is a resistive load, and will not induce a voltage in the water. If the heater cord is in the water, situate the heater so the cord is not in the water. If the 27 volts does not appear, rather you get 5volts, replace the heater as the cord has some problems. Often manufacturers that make electrical equipment for aquariums do not use cords that are suitable for submersion in water.

 

[Capt_Dan]

Great info! I usually find mine by getting shocked! LOL

 

[sfsuphysics]

Yup, have a hangnail? Yank that bad boy off and make sure some skin tears with it, then standing in wet socks put that finger into the tank, and voila!

 

[leviburns89]

Ok, I really am kicking myself for digging into this topic...

But Uncleof6....

Your discussion on ground probes makes sense, why complete a current, when the flow in itself is harmless until grounded.

My question:

If a piece of equipment is in fact faulty, and there is in fact current in the tank from equipment, isnt it safe to say that the tank is "potentially" grounded?

All it takes is a single molecule of water to transfer electricity to another media.

I agree completing the circuit via grounding probe is bad. But if you are in fact experiencing an electrical sensation, that means somewhere in the tank, there is a ground.

Correct?

I may just be rambling, I just read this whole article, roughly 2 hours of solid research. Brain is fog...

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[bluefronted]

Good info,

I got zapped slightly a few times the past week on my fingers that have cuts. Stray V/I coming from my Eheim 5000 + Compact return pump.
Will measure the V this afternoon

 

[mcgyvr]

Good info,

I got zapped slightly a few times the past week on my fingers that have cuts. Stray V/I coming from my Eheim 5000 + Compact return pump.
Will measure the V this afternoon

GFCI protection (RCD in countries outside the US) should be a MUST for any submerged line powered piece of equipment..
Then being exposed to voltages due to faulty equipment becomes a non-issue..

 

[gargoylenest]

theres a lot of funny post to read. been working in electronics over 20 years, and id never put a grounding probe in my tank. In regard to those concerned about a few volts or a few milliamps, unless you have a high quality multi meter, its mostly inaccuracy from cheap *** walmart equipment. About stray voltage, see it like static electricity; unless you ground yourself, you dont get a shock and dont even know your electrical potential.

 

[vikinglord13]

Thanks for the video!