Questions about stray voltage

[astreck827]

TLDR; I felt some stray voltage in my tank and I can't find the source, but I have an anomaly with the readings when unplugging a powerhead.

I have scoured google and the forums for answers about some stray voltage issues and I can't seems to pinpoint exactly what I am dealing with, hoping someone here can give me some insight. I think I am dealing with stray voltage in my system. I have tested using a multi-meter in the past and my readings were right around 19-20 AC volts. My research has suggested this is pretty normal, but when I was doing some tank maintenance recently, I got a definite buzz on a small cut in my hand. This ONLY happened when I would kneel down and put my bare knee on the floor - when I stood up wearing shoes, there was no sensation besides the usual saltwater burn. This tested true across all the tanks in the system. I broke out the multi-meter again and got the same number as before. I have quite a bit of equipment in my system - it is a total of 6 tanks + a Rubbermaid sump and a separate return tank. Using the meter, I tested each piece of equipment by unplugging one at a time. The average drop was about 0.5-1.5 volts per item, so I am assuming this was the inherent induced voltage. The only anomaly was a Nero powerhead that I got used - when I unplugged it, the voltage actually INCREASED by about 2 volts. When I plugged it back in, the voltage went back up. The cut on my hand that I had last night has healed and I can't feel anything in the water anymore, so I can't really put that to the test, and I don't really feel link wounding myself in order to use my body to test for electricity in a 300 gallon saltwater system.

Everything is plugged into GFCI outlets. They are spread across several outlets and 2 circuit breakers due to the size of my system and the amount of equipment I'm using. I have the multi-meter set to AC volts with a sensitivity of 200. I will attach a picture of how the meter is set to confirm it is correct. Does the anomaly with the Nero powerhead make sense for it being the source of the leak? Or is there a better way to test for "true" stray voltage versus induced voltage? I am concerned first and foremost for my safety, but also I have had some mysterious acro deaths that have happened in a blink of an eye and I'm wondering if voltage is the killer.

 

[Lbrdsoxfan]

Maybe stray voltage. Last round of that, I had a cheap powerhead rot out the cord right where it enters the back of the potting. Couldn't find it at first as it was intermittent, but after some investigation, it revealed it's self (it came apart in my hand). I didn't have a grounding probe but everything is GFCI for me.

 

[astreck827]

I have read grounding probes are actually not good for the inhabitants of the tank because it gives the current somewhere to go and therefore is more deadly.

 

[Aspect]

Unplug everything and plug back in one at a time.

 

[Aspect]

Also, you don't need a cut in order to be grounded and feel stray electricity. But it's not the smartest way to test either, invest in a grounding probe.

 

[astreck827]

Unplug everything and plug back in one at a time.

Honest question, what makes this better than unplugging one at a time? And what am I looking for? Everything in the tank is generating about 1 volt.

 

[Aspect]

Honest question, what makes this better than unplugging one at a time? And what am I looking for? Everything in the tank is generating about 1 volt.

You need a grounding probe, once you have the grounding probe grounded you plug in one at a time until your grounding probe trips your gfci. Then you will know what is causing the stray voltage.

 

[TheyGaveItToMe]

Honest question, what makes this better than unplugging one at a time? And what am I looking for? Everything in the tank is generating about 1 volt.

Did you ever figure this out? I'm just curious, where did you positioned the leads for the multi-meter? Because, just dropping both leads into the tank isn't going to give you a reading that means anything. To detect voltage in the system you need to have a lead in the tank and the other going to ground. Electricity travel path of least resistance, and both leads in the same tank don't make a circuit.

 

[astreck827]

Did you ever figure this out? I'm just curious, where did you positioned the leads for the multi-meter? Because, just dropping both leads into the tank isn't going to give you a reading that means anything. To detect voltage in the system you need to have a lead in the tank and the other going to ground. Electricity travel path of least resistance, and both leads in the same tank don't make a circuit.

I was putting the black lead into the ground terminal of a GFCI grounded outlet.