Grounding Probes

[MikePowell]

reefergeorge-

what else could i habe done. my house has two wires only, with out updating the wires in my house i found this the most effective way to "fix" the problem. i did try the GFCI outlet but it did not prevent the stray voltage in my tank. it was not a shock from a short circuit just some stray voltage. my problem was that the tank or any of the pumps or lights were not grounded through the recepticle.

 

[m2434]

<a href=showthread.php?s=&postid=11496453#post11496453 target=_blank>Originally posted</a> by MikePowell
reefergeorge-

what else could i habe done. my house has two wires only, with out updating the wires in my house i found this the most effective way to "fix" the problem. i did try the GFCI outlet but it did not prevent the stray voltage in my tank. it was not a shock from a short circuit just some stray voltage. my problem was that the tank or any of the pumps or lights were not grounded through the recepticle.

What do you mean by stray voltage. If you test saltwater it will always show a voltage, this is because of the ionic nature of saltwater - there is always a voltage potential and when you test it, you are creating a ground and causing current to flow. So you get a reading, however this is sort of a "false" reading because it actually is caused by you and goes away once you stop testing, or remove the ground probe. Readings of up to 10 volts are fairly common due to the ion flow in the salt water alone and not usually a concern.

The concern is a piece of equipment malfunctioning and electrocuting you when you put your hand in the tank! If you test the water and get a reading of 120V you are in trouble, and your fish are probably dead...

 

[cczarnik]

<a href=showthread.php?s=&postid=11487489#post11487489 target=_blank>Originally posted</a> by reefergeorge
I would have to totally agree. I would never use a GP in my tank. Just use a few gfci circuits and you will be ok, and Ccz your fish were not electrocuted.

Just came back to this thread.. I appreciate the comment, and although I'm not a professional electrician I have seen this first hand. And such losses give cause to really think about what went wrong! When the heater blew, the hot and common wires of the heater were both exposed to the water. This effectively put the water and the inhabitants in the current path and they suffered the consequences. Just like the bird example that has been used. And this tank WAS on a GFCI, but it didn't matter as the heater was non grounded, so the voltage/current took the same "hot to common" path-- the GFCI never saw the difference.

When I put the ground probe in an alternate path was created that allows stray current to exit through that ground path, which would trip the GFCI.

I'm not really worried about stray voltage, and the voltage / current comments are valid. But I'll tell you when you have a 15A 120V circuit exposed directly to the tank, you got both. And if there isn't a ground path around a GFCI there is a BIG problem.

There's a real easy way to test this Cut off the cord of an ungrounded lamp, plug the cord into your GFCI and stick it into the tank. No ground probe- no GFCI trip. Your livestock won't be too happy though I'll assure you... Do the same thing with a ground probe and you'll see an immediate GFCI trip. Try this little experiment at your own risk I've learned my lesson! Chuck

 

[cherubfish pair]

Okay cczarnik, I need both a GFCI and ground probe. Do I plug the ground probe into the GFCI, or into the wall? And do I put the ground probe into the display or sump? I was told if I have electrical equipment in the display I need a ground probe in there too.

 

[cczarnik]

Doesn't matter. Ground is ground. As long as your GFCI is wired correctly and the neutral is isolated from ground per the GFCI instructions, you're OK. Plug the probe into any outlet, or if it has an eyelet, screw it to a known ground, the screw that holds an outlet cover on should work, or to the frame of any large metal applicance, computer, or anything that plugs in with a 3 prong cord. This is assuming your house is 3 wire (99% are). I think there are even solutions for 2 wire, but others should chime in here.

I haven't had a display/sump yet, and haven't really done the research on multiple ground probes. My guess is the water column in the plumbing would be sufficient to carry stray current from one tank to the other and find the probe. But it's not like they're that much $$.

Maybe what happened to me was 1/1,000,000.. All it would take was for the mfg's to start grounding these devices and things would be much safer. Kind of silly to think that we submerge high voltage devices into corrosive solutions and leave them there for years. One day somebody's going to get killed. Then comes the massive recall and we'll all look back on it as an idea as stupid as lawn darts. Ha! Chuck

 

[cherubfish pair]

So when there's a stray voltage the GFCI gets tripped and the power goes off for your entire system?

Is there some kind of alarm you can get to go off when this happens? Otherwise your livestock can be in a very lethal situation.

 

[aspinn]

aye i will be using one for sure once i get it set up... at the moment our house is old... the wiring is poorly done so i dont trust it at all (not to mention we have all carpets and ud be amazed how many times i shocked myself --- although does static shock bug the tank at all?... either way ill be going for it... i wasnt sure if static shock does bug them or not lol (you think it would lol) like the others said better say then sorry

 

[cczarnik]

Cherub, You could always go for something like:

http://shop.talkaboutsleep.com/?action=item.display&category=power-failure-alarm&page=90100

On my big tank I'll keep the external sump return pump off of the GFCI, so if I do get a trip the circulation won't stop completely. It's grounded and not submerged, and would prevent a crash.