stray voltage questions.

[rotarygeek]

I have seen a couple threads about stray voltage, but i dont know what it is. So can someone break it down for me and explain what it is and how you test for it? Also what its supposed to be and how to correct it if i end up with wrong readings. A little info about my tank is
30 gallon tall.
a full hood with a 24 inch flurescent (sp?) light strip
a 170 gph powerhead
a 110 gph powerhead
a penguin biowheel 350
a stealth 250 watt heater.
Its all on one powerstrip and the light is on a timer from walmart. if someone could provide some info about what it should be and what i can do to test it it would be greatly appreciated. I aslo have a voltage reader if that helps.

 

[gmann1139]

Stray voltage is the leaking of electricity from your electrically powered elements inside the tank (heater, powerheads, etc.) into the water.
Its dangerous for both you and your fish, and the reason everything that your aquarium system should be on a Ground Fault Circuit Interrupter (GFCI). These are the same type of outlets in your kitchen and bathroom, as they have the same potential for mixing electricity and water.
If you have a stray voltage problem, you may notice that you get a shock when you touch the aquarium water. If that happens, or if you think for another reason you have a voltage leak, you can test the tank.
IF YOU HAVE BEEN SHOCKED BEFORE, DO NOT PUT YOUR HAND BACK IN WHEN THE POWER TO THE TANK IS ON!
Same thing if your GFCI trips. It may be because something has failed to ground. Your safety is paramount. I recommend always powering down the tank before reaching in.
If you've been shocked or the GFCI has tripped, check out your heater and powerheads for obvious damage.
Here's how to test for stray voltage:
1. You'll need a multimeter that can measure voltage. Set it to the lowest AC setting (AC = ~, probably 2 V or 200 mV is the lowest).
2. Put the black lead into the ground of an electrical outlet (preferably on the same outlet your heater/lights/PH are plugged into.
3. Put the red lead into the water. Your meter will jump around, but if you're reading more than 10 mV, you may have a problem.
4. If so, unplug each element that is physically in the water one by one, until the Voltage drops significantly. That's the element that's leaking voltage. Start with your heater, as they are the #1 offender.

 

[rotarygeek]

yeah so its what i thought it was. so im guessing a quick way to tell if you have stray voltage is if everything dies is short order in my tank, which hasnt happened. i have never been shocked except by my powerstrip with a wet hand. should i be testing this too?

 

[gmann1139]

Actually, your livestock won't necessarily die quickly.
Depending on the severity of the electrical leak and its location, the 'circuit' may not be complete until you come along. Remember, you've got a great conductor (SW) enclosed inside a great insulator (glass/plastic). THere's no 'easy' path to ground, so the electricity won't flow until you touch the tank, and provide a place for it to go.
I'm not sure what you mean in your last sentence, but that sounds like a perfect situation where a GFCI in that line should have tripped, unless the shock was just built up static electricity.

 

[rotarygeek]

no this was me being danger near electrocuted. about a good 4 seconds of electricity. it sucked. i guess i didnt have the plug on something all the way in.