Stray voltage

[OoooDRAGONoooo]

Hi all,I wa bending over my sump and a tiny part of my nose touched the tip of the glass.it felt like something sharp touched me but when i checked it was smooth,I quickly realised it was a very small electric shock.i put my nose on it again and I got another tingle.so I got on the web and started reading about stray voltage.many threads blamed this phenomenon on faulty heaters/pumps etc,but after experimenting with a meter I discovered that there wasn't just one or two offending appliances but ALL of them added varying amounts of current/voltage to the tank,even my sump lights which are not touching. (explain that!). So it seems the conscensus of opinions is that sending this electricity to earth would have a detrimental effect on the inhabitants more than ignoring it.its certainly not practical to remove all the heaters ,power heads,skimmer,lights return pump etc etc ,so what is an agreed acceptable level not to be concerned about or are all marine tanks doomed to reduced life expectancy of coral /fish?

 

[myram]

What is your measured voltage in the water?

 

[AirForceAquariu]

I highly doubt that every piece of equipment is realeasing stray voltage. How did you isolate each piece of equipment to check? Did you unplug all but one, test it, and then repeat for each? If not then the offending piece is likely throwing off your reading. Have you noticed anythign erratic in the tank? If there was stray voltage things would be behaving oddly or suffering.

Also, you mentioned feeling the shock on the glass but never said anything about in the water. You could just have a high amount of static electricity in your home. It is winter, and with the dryer air there is a lot more static to go around. You may also want to check on the grounding of your electrical system which may lead you to a more serious and pervasive electrical problem.

Also, I hate to be dismissive, but your sump lights could not be adding voltage to the tank if they are not touching it. Well I s'pose they could, but the arc of electricity would be rather noticeable and would be more then "stray" voltage. I think a calibration of the voltmeter is in order along with some practice using it.

I wish you luck in figuring out if you have a faulty piece of equipment and hope it's nothing more then some static letting your tank "boop" your nose.

 

[ReefsandGeeks]

The consept of stray voltage in an aquarium is pretty new to me, but i'm curious how you measure it. do you take your voltmeter and check voltage between the aquarium water and the ground plug on an outlet? For anyone worried about static shock causing damage with something like this (not sure if it's a problem to fish or equipment) you could attach a strong resistor to one end of the meter so it the shock is very gradual reletive to no resistor. interested in reading about this problem

 

[OoooDRAGONoooo]

Shock

Shock

Hi,ty 4 your replies.i put the positive probe into the tank or on the glass and the other probe onto the earth terminal on wall socket.with all appliances turned on I get around 50 volts showing.as I unplug each one in turn the voltage drops.as an experiment I went to another room, got a bucket of tank water and tested it for voltage,there was nothing registering as expected,I then submerged a 1200 ltr per hr pump ( new ) and switched it on,It showed around 4volts on the meter,so definitely each of the appliances has a compounding effect on the total, (some more than others).something I don't understand also is why the glass of the aquarium is conductive,maybe it's the fine invisible salt mist that may be present.strange too is I get a large reading from a clip on led sump light even when I plug it into a separate socket.all the fish seem to be acting normally as well as the crabs and snails.with regards to the Meter ,I set it to 250 ac and the reading needle moves to around the 50 mark.i put my hands in the tank and even licked the top of the sump and no shock.

 

[myram]

50 volts is quite a bit, definitely enough to give you a good tingle if you are barefoot and complete the circuit.

I normally have 1.9 volts of stray voltage in my sump.

 

[amber3k]

I'm curious to hear more opinions. I asked this question a few months ago and was told there should be no stray voltage. I show 12v and it doesn't matter what is plugged in. I think the meters can pick up current that is nearby. I kept thinking I was being shocked when working in the sump also, but I've narrowed it down to one thing. I have dry hands, very small breaks in my skin and only get shocked when working in sump, not dt (which shows same voltage). I think the micro bubbles from the skimmer popping saltwater in my cuts are making me think I'm getting shocked, if that makes sense, the sting feels the same as a shock.

 

[Paul B]

Every electrical appliance you put in or near your tank will induce some voltage in the water. Voltage will also be induced in to you when you hold a drill or any electrical appliance. It is normal, you can't stop it from happening but you can stop putting your nose in the tank.
(Master Electrician 40 years)

 

[OoooDRAGONoooo]

Ty it was as I suspected, not just one but all donating current.question is,is 50 volts ok or are the inhabitants going to suffer?

 

[myram]

Stray voltage is only an issue when the circuit is completed..........as in a grounding probe, or you putting your hands in the water.

A while ago I posted a link to an interesting article in another thread about this. If I can find it, I'll post it here.

 

[myram]

Found it.........

www.reefcentral.com/forums/showthread.php?t=2182599

 

[wolfblue]

I always wonder when I see these threads pop up... Induced potential but no path to ground, no current flow. But you put in a ground probe- could you start making chlorine?

 

[mcgyvr]

Its HIGHLY recommended that any equipment submerged in an aquarium be protected by a GFCI device (either a power strip with it or replacing the outlet with a gfci outlet or the breaker with a gfci breaker)..
IF there is a problem it will find it way better than any inaccurate hobbyist voltage test which is basically proving nothing other than your meter leads make a great antenna.
Just hold the leads around a fluorescent light bulb or near any electrical device in your house and you will see the meter move..

Had there been a real problem though and you don't have a GFCI you "could" have been electrocuted. Call yourself luck and head out to the hardware store now.
And if a problem is there or develops at a later date that GFCI will let you know immediately.