Electricians needed: stray voltage with everything unplugged

[dixiedog]

My tank only has two submerged motors - the skimmer and the return. There is a heater of course, but it is unplugged for the summer. My only powerhead is a Vortech.

With both pumps running, I have 24 volts in the tank.

Unplug the skimmer: 17 volts.

Unplug the return: 14 volts.

And that's it. Nothing else to unplug. So I have to assume I'm backfeeding some current from the house, right? How do I fix it if that's the case?

It's late and the wife and kid are in bed so I can't get started on it tonight, but I'd like to start poking around in the breaker box tomorrow after work. I can post a photo of the box tomorrow too, if that helps.


BTW there's no GFCI, which I realize needs to change. I used to have one and it just tripped all the time so I ditched it.

 

[billsreef]

Have checked with lights unplugged as well?

 

[bluewater921]

build a grounding probe or buy one .. thats about the only way to really cure the stray voltage ..

 

[Landsailor]

BTW there's no GFCI, which I realize needs to change. I used to have one and it just tripped all the time so I ditched it.

Ummmm, yeah. That's as bad of an idea as replacing a 10A fuse with a 20A because it keeps blowing or screwing a penny behind one of the old style fuses.

If a GFCI is tripping, the chances of it being faulty are much, much, much less than the chances of you having a problem. You've just shown that you have a problem.

 

[jerpa]

build a grounding probe or buy one .. thats about the only way to really cure the stray voltage ..

Only place a grounding probe in your tank if you re-install a GFCI receptacle. Echoing the statement above, if you had a bad outlet changing it would have solved the nuisance tripping. If that did/does not then it is tripping for a potentially dangerous reason.

 

[dixiedog]

Have checked with lights unplugged as well?

Just now.

I run a 4 bulb T5 with two power cords. Each cord you unplug removes one volt from the water, which I can't understand. Obviously the fixture doesn't touch the water (it's suspended from the ceiling BTW) and neither do the cords. And there's no salt creep anywhere.

And if that weren't enough, it seems the Vortech adds two volts as well!

build a grounding probe or buy one .. thats about the only way to really cure the stray voltage ..

I've always run a ground probe. But it has recently been brought to my attention that (basically) a ground probe without a GFCI is useless at best, harmful more likely than not, can cause a house fire, and kill you.

 

[dixiedog]

To recap:

With everything running, I have 28 volts in the tank.

Unplug the skimmer: 17 volts.

Unplug the return: 14 volts.

Unplug one light cord: 12 volts

Unplug other light cord: 10 volts

Unplug the Vortech: 8 volts.

With absolutely everything unplugged, power strip and all, receptacle empty: 1.5 volts.

 

[cpt cautious]

I wonder if that stray voltage is coming from a ballast or something that is holding energy still. if you unplug everything and leave it off for a bit is there still that 1.5?

i wonder how much voltage is in my tank if you get that much from everything..

 

[srusso]

I don't think anyone has asked, how are you testing the water for voltage? Is your meter working proper? I understand your getting a reading, maybe test a 9v battery to ensure your getting a correct reading?

 

[lecher]

Personally, I would reinstall a GFCI (and test periodically), ditch the ground probe and call it a day. Most tanks have small amounts of stray voltage. Without the probe the voltage is not going anywhere and is not doing any harm to its inhabitants.

 

[jerpa]

The 1.5 volts you are reading with everything unplugged is the electrical charge of the aquarium itself. Stray voltage really is meaningless. Current is what kills. I would install a new GFCI and see if the tripping problem continues. If a grounding probe makes you feel better use it with the GFCI. You are most likely just reading the voltage induced by any electrical field near the aquarium or merely by the movement of the various ions in seawater. In order to truly put it to rest measure the current between the aquarium and ground.

 

[HECS]

I would consider checking where your standing, I've seen instances where the moisture or conductiveness of the ground your standing on is carrying stray current from a broken wire or cord. In your case, the result could be a path of least resistance through you and into the aquarium (very conductive). If you can't find an obvious source of the problem, consider a getting an electrician to check the main ground, and neutral bond in your main service. You could have stray voltage from an ungrounded system or disconnected neutral. -Somthing a GFI won't protect you from, and can cause a fire on a high current circuit. Be Safe!

 

[Craig pc]

I work in the electrical field check the main ground in your house outside you should have a main grounding rod more times then I can count your ground gets broke and now your tank is your ground power needs a reference to function properly ie a common that's grounded at the main electrical bus. This could be broke or way undersized

 

[billsreef]

Considering the minor voltage changes with each piece of equipment, that 24 volts could be just induced voltage. I'd start with Jer's recommendation and go from there.

 

[dixiedog]

Considering the minor voltage changes with each piece of equipment, that 24 volts could be just induced voltage. I'd start with Jer's recommendation and go from there.

Okay, that's what I'll do. I googled "induced voltage" but still don't really get it, but I can infer the basic meaning, I think. I will also check the physical ground of the house, as suggested. It's an old mobile home and could very well have issues.

Would you experts suggest an actual GFCI breaker, perhaps?

 

[jerpa]

I prefer GFCI outlets so one bad piece of equipment doesn't take down the whole circuit. If your only using one outlet for your tank then it's a moot point as far as the tank is concerned.

 

[staindsoul]

A gfci measures the balance of current between the hot and nuetral by using a transformer. If they are unbalanced, ie. current leaking to anywhere but the nuetral, a shunt trip takes the circuit out. With that it is always critical to have one on a reef for your safety. The one that was tripping was more than likely bad.

Hecs unless he is barefoot that's really not valid and then barefoot standing on concrete or conductive material. jerpa tell a lineman that voltage isn't harmful and see what he says. "Stray voltage is meaningless" tell that to a cattle farmer.

Are you going from receptacle ground to the tank with probes?

Gfci breaker or receptacle works the same, either will be fine.

Induced voltage is a result of a magnetic field running through a conductor that induces a electrical charge on a neighboring conductor that is not apart of the first conductors circuit. Stray voltage would be your culprit depending on how your measuring this. That's what I am curious of.

I am not trying to start a argument with anyone or troll. I am a licensed electrician in va and have been in the industrial controls part of the trade for 8 years now. I don't know a ton about reefs but I do know about electrical work and am just trying to help op out.

 

[jerpa]

A stray voltage reading without knowing the current is meaningless. I never said harmless. I stand by that statement.

 

[dixiedog]

Are you going from receptacle ground to the tank with probes?

Yep. I'm holding one probe between my toes (seriously) in the receptacle ground, other probe dangling in the sump whilst I unplug things, and check readings.

Gfci breaker or receptacle works the same, either will be fine.


Okay cool. I just thought maybe the breakers might be more reliable than the outlets. A bit more money too I'm sure, but this is not an area worth skimping on.

Stray voltage would be your culprit depending on how your measuring this. That's what I am curious of.

I'm using a digital multimeter from Lowes. "Ideal" brand? It's black and yellow, seems to be decent quality. I use it with an Apogee sensor to take PAR readings. It gives consistent, predictable readings as far as I can see.

 

[cheezischrist]

im just confused, but ive never ever had voltage in my tank, except in two instances where heaters cracked. and one other where tank was overflowing into cheapy 3way extension chords.