# Stray voltage



## noddy (Nov 20, 2006)

I just had my hand in each of my five tanks and felt a fairly decent amount of shock in a cut I have on my finger in three of the five tanks. I immediately checked to see if it was coming from the Maxi jet 1200s (I replaced one a month back because of this reason) and it is coming from those three powerheads. The two tanks that didn't give me a jolt were one that doesn't have these units and the one that I replaced recently. Is this a common issue with these units? What causes the unit to do this after time? And is there anyway to fix this problem without throwing the things away? Thanks for any thoughts on this.


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## oyster dog (Jul 2, 2013)

Powerheads and heaters are notorious for producing stray voltage via induction. A Google search on this topic will yield hours of reading. The bottom line is all submersed electrical equipment can produce induced voltage. Some lighting systems will also produce stray voltage, and they are not submerged.

I used a voltmeter to measure the amount of stray voltage by turning each piece of equipment on and off. My heater produced the most, but as my fish are all fine and don't react when the heater is on, I have decided to live with it.


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## Deeda (Oct 12, 2012)

It is always possible for electrical aquarium equipment, especially submerged units, to leak where the wire enters the body of the unit. This can occur due to a faulty seal, aging of the unit, stress on the cord, accidents and occasionally manufacturer defects or problems.

I don't know if power-heads, submersible pumps and heaters are just the more common products that seem to have these problems but it seems as if those are the ones that are usually subject to more frequent handling and possibly twisting of the wires during maintenance and positioning in the tank.

I don't know if a well placed dollop of silicone sealant will properly seal the area where the cord enters the unit. Some people have done this and had good results for a while. I haven't personally experienced this problem yet so I can't offer any first hand advice but for any equipment over a few years old, I would probably just replace it.


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## oyster dog (Jul 2, 2013)

Note that there are two different sources of electric currents in our aquaria: 1) shorting, or leaking voltage, which is caused by a defective device, where water is in direct contact with the electricity flowing into the device and it needs to be replaced; and 2) Induced voltage, which is caused by a spinning magnetic impeller, which acts as a small generator and produces low voltage with little current. The electricity flowing into this device is not in contact with the water. Heaters can also generate induced voltage, as can fluorescent lights.

You can use a voltmeter to help distinguish the two. A short can produce a large current, while an induction will produce a smaller current. I've seen guidelines for saltwater aquariums, but not for freshwater, probably because the conductivity is so low in freshwater.


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## noddy (Nov 20, 2006)

Thanks for the replies. I think I will replace the powerheads as I bought them all roughly at the same time. I have heard of fish developing a curvature of the spine do to stray voltage (not sure if there is any truth to it), and I was speaking to someone today that thought it does no harm to the fish. Is there an immediate threat to the health of the fish? As far as I go, I found wearing a pair of shoes in the fishroom makes a whole lot of difference


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## sumthinfishy (Jan 26, 2013)

no harm. its bird on a wire syndrome. even if water has voltage leaking into it, the fish will become the same voltage as the water. its known as "being at the same potential". as long as fish is at same voltage as water than nothing will happen. only if fish were to become a path to ground or "a different potential" thats when it becomes a problem. just like a bird on a wire. the bird is at same voltage as the wire(no danger) only when the bird comes in contact with a grounded piece of equipment does it become a problem. the bird completed the path to ground which is whats dangerous. i'm a lineman for the electric co, and have personally seen demonstrations where an extension chord with a light bulb on the end is submersed in a tub of water while being held in someones bare hand without an incident. why are u killed if an electrical item that was plugged in were to fall in to bath tub u ask? because pipes connected to tub are grounded, and u become part of path to ground. if u were in an old clawfoot tub with no pipes conected to it the u could sit in it full of water all day with a plugged in extension chord in tub with u and be fine. i know its a long winded explanation, but fish will be fine. however, if your piece of equipment is three prong (grounded plug) then there is a risk of completing circuit and killing fish. a three prong or grounded piece of equip that is leaking voltage is ok, but if the exposed wire where voltage is coming from also has an exposed equipment ground, then your tank could become a different potential or complete the circuit to ground killing everything. hope this helps, but either way its some usefull info


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## noddy (Nov 20, 2006)

Thanks for the reply, I figured it was safe due to them not being grounded. What about danger to me? If I was to grab hold of one of the steel studs in the wall when my hand was in the tank, would I be toast? I suppose it would depend on how much voltage was in the tank.


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## sumthinfishy (Jan 26, 2013)

def depends on how much voltage. its actually amps that kill not voltage, but that is another whole lesson. haha. it doesnt take much voltage to cause your muscles to lock onto something. high voltage contact will blow u clear, but low voltage contacts will lock u on and slowly cook u. i seriously doubt u have to worry though with the small amount of stray voltage that we are talking about


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## noddy (Nov 20, 2006)

Thanks again, I'll keep my shoes on until I get the powerheads replaced


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