How to test for stray voltage?

[luntiz]

So today I placed my hand into the tank to clip some seaweed for my tang and I got a slight shock to my finger. I have carpet and was told that sometimes carpet can create that shock but I'm not too sure. Well anyways, whats the easiest, safest, and quickest way to test for stray voltage? No wonder my tang sometimes acts skittish...

 

[BlueDolphin]

luntiz,

I went to my LFS and they let me borrow their voltage meter. It was easy - one probe went in the tank water and the other in the electrical outlet. If the needle moves on the meter then you have stray voltage. You should check and see if you LFS has a meter you can borrow.

HTH!

 

[youronlysin]

Thats a tough one. If you just got a quick zap like when you touch the light switch after crossing the carpet, thats just static electricity and there isnt much you can do about that. Even if you ground every metal piece of equipment and put a ground rod into the tank, its still going to be at a different potential than your body after walking across the carpet. That wont hurt your fish though, either. The water or something on the tank might be at a different potential than your body standing next to the tank, but the fish in the tank will be at the same potential as the tank itself, so they are safe.
Now, if your heater or some other piece of equipment that is in physical and electrical contact with the water is cracked and allowing water to penetrate its seal, then you could have a more serious potential between you and the tank. I would also tend to think that if something were leaking or allowing water inside it that it would quit working, unless only one conductor were in contact with the water. If the hot or neutral conductor in say, your heater, were in contact with the water then youd deffinitely feel it should you touch the water; the fish might still be fine because they are at the same potential as the conductor that is in the water. If the potential between the water and the conductor were different, youd blow a breaker or a fuse or something.
Measuring a stray voltage could be impossible without some expensive equipment like an ESD tester or static meter. You could check with a standard VOM to see if there is much difference in potential, or read the resistance between the tank water, components and an earth ground. If you stick the leads of a VOM in the water and one lead to a good ground and you read a high voltage then you seriously have a problem. Then you need to check the wiring for your heater or anything else electric that comes in contact with the water.

 

[youronlysin]

A stray voltage from what? Instead of checking for a voltage between the water in the tank and an earth ground, Id be more concerned with checking for 120VAC at the plug where each component is plugged in. In the least check all of the wires and make sure the heater isnt cracked or have moisture inside it.
You might very well read 40 or 50 or 60 volts AC if you measure between the water and an earth ground but that shouldnt be any cause for alarm. If you measured an extreme voltage then Id merely check wiring for damage. Thats it. The only way your fish are going to know any different is if you complete the circuit for current flow from their tank to ground with a wire. i.e. like your VOM leads

 

[luntiz]

Ease up on the electrician talk. I have two power strips, 6 outlets each that are connected to 2 wall sockets. I have 12 outlets and about 8 of them are used. 1: Heater, 2: 2 PowerFilters, 3: 3 Powerheads, 1: PC Lighting, and 1: Moonlights. So are you suggesting that I test the 2 wall sockets or the 12 outlets from the powerstrip?

As of now I unplugged the heater, one of the filters, one of the powerheads and have turned off my PC lighting. At times I still feel a slight shock in the water. I'm not sure what it is, I have carpet but most of it is covered by a thick plastic floor thingy...w/ a bunch of pointy ends to "plug" into the carpet.

 

[luntiz]

There is a slight cut on one of my powerhead powercords. I don't see any wires or anything but there is a cut.

 

[youronlysin]

I'll assume that your power strips have circuit breakers in them. If there is a dangerous situation present, the circuit breakers would open. If that isnt happening, I dont think there is anything to worry about. Without going into any of the technical aspects of electricity, there really isnt any way to explain how this isnt a problem for your fish.

If you want to be positive that your tank is protected, then you should replace the two outlets in the wall with GFCI outlets and make sure they have a good ground connection. (The GFCI outlets will need a proper ground in order to work properly).
If you have a newer house with up to date electrical wiring, then you more than likely have properly grounded outlets.

 

[youronlysin]

Remove the powerhead with the cut cord and see if you still feel the shock when you touch the water.

 

[luntiz]

http://catalog.belkin.com/IWCatProd......essories/PowerStrips/HomeOffi...erStrips/# I have a belkin, similar to that above, but probably an order model. Got them from HomeDepot for like 7 bucks each. Maybe I should invest in something better.

 

[luntiz]

http://catalog.belkin.com/IWCatProd...tanleyP...essories/GFCI/ContractorGradeGFCI/# Is this something I should invest in?

 

[luntiz]

I believe this is the exact product, http://catalog.belkin.com/IWCatProd...t_Id=&Section_Id=75&pcount=&Product_Id=125402

 

[youronlysin]

The inline GFCI would deffinitely protect you or your equipment. They have GFCI outlets that go right in the wall in place of the normal outlet as well. If you have a newer home, they usually have those kind in the bathroom and at least one in the kitchen near the sinks. They have the little reset button on them. If you are sitting in the tub and drop a hairdryer in, the GFCI outlet will trip so fast you may not even feel but a slight shock. GFCI outlets are always a good idea when using power around water. The expense is up to you.

Its important to note that even with a GFCI outlet, you might still feel a slight shock when you touch the water because there may not be any current flowing untill your body completes the path. If the GFCI doesnt trip when you touch the water, then the amount of current flowing when you feel the shock is minimal and probably not dangerous. If the GFCI does trip when you stick your finger in the water then you need to find out what piece of equipment is in contact with the water and causing the problem. Either way, as long as you arent "completing" the circuit by sticking your finger in the water your fish dont feel a thing. Check on that power head first. Then we'll see where to go next.

 

[luntiz]

Either way, as long as you arent "completing" the circuit by sticking your finger in the water your fish dont feel a thing. Check on that power head first. Then we'll see where to go next.

So you're saying that without my finger in the water, the fishs won't feel a thing? But does the equipment in the water leak out voltage that is creating a tank full of electricity?

Well anyways, I'm down to 1 Powerfilter and 1 Powerhead to keep the surface aggitated.

 

[youronlysin]

A good power strip is always recommended. Most power strips are "surge" supressors meaning, they will prevent any surges, or sudden electrical spikes from reaching whatever equipment is plugged into them. If they have a built in circuit breaker, even more the better. The circuit breaker will trip if any of your devices plugged into the strip try to draw too much current...i.e. you drop a light fixture into the tank or something. There is a difference between a GFCI outlet and a circuit breaker however, as a circuit breaker would only trip if something were to draw at least as much current as the breaker was rated for. Most power strips are rated at around 15 Amps. Thats a lot of current. The GFCI will trip when differences in current are in the milli-amp range and they also trip in a matter of micro-seconds. You could get quite a jolt before a circuit breaker tripped whereas, you may not feel a thing if you had a GFCI outlet installed.

GFCI outlets protect you. Circuit breakers protect the electrical system from overloads (too many devices turned on at the same time). Surge protectors protect whatever equipment is plugged into them.

 

[luntiz]

Okay, Well I checked under the powerstrip and it is a "surge suppressor" It also states that its not meant for aquarium use. Speaking of lighting dropping into the tank, that happened to me 2 weeks ago. Could that have caused a problem with out equipments?

 

[youronlysin]

Either way, as long as you arent "completing" the circuit by sticking your finger in the water your fish dont feel a thing. Check on that power head first. Then we'll see where to go next.

So you're saying that without my finger in the water, the fishs won't feel a thing? But does the equipment in the water leak out voltage that is creating a tank full of electricity?

Well anyways, I'm down to 1 Powerfilter and 1 Powerhead to keep the surface aggitated.

Yes. Thats what Im saying. The equipment in the tank could very well be doing this. But without a way for any current to get to ground, then your fish wont feel a thing.

 

[youronlysin]

unless the lighting is still in the tank 8O it shouldnt be causing any problem. Whatever is creating the voltage potential would have to be in direct contact with the water if you can feel it when you stick your finger in.

 

[youronlysin]

Can you feel a constant sensation as long as your finger is in the water, or is it just a quick zap and then nothing else?

 

[luntiz]

I think its a constant sensation, not really sure, but I know that after I take my hand out of the tank, my fingers feel...numb...or something, can't explain. I always thought it was because I was grabbing the rocks so much that the rocks were cutting my fingers. I will have to check tomorrow.

Currently running my Powerfilter and 1 Powerhead and my Moonlights. Hopefully I unplugged the equipment causing the problem.

Off to bed I go, hope you as quick to answer my questions tomorrow. Thanks for taking your time this evening to answer my questions and provide a lot of information (althought 1/3 of it I didnt really understand)

 

[youronlysin]

No problem! Its hard to explain electrical problems sometimes, sorry for that. Tomorrow, try unplugging equipment one piece at a time and see if you can notice if the shocking quits. You should be able to find the faulty equipment that way...if it truly is the equipment that is causing this. Good luck!