Grounding probes
- Thread starter joemama65
- Start date
stricknine
New member
My opinion is the GP will do both. Grounding the water or system will introduce a direct path to ground to provide a reference point for faults, and provide a safe path to ground for stray voltage. Stray voltage can occur for a number of reasons; electronic devices,motors, inductance, reactance, harmonic distortion but are very small voltages and isolated from the electrical system and thus not picked up from the protective devices in your homes electrical system. Grounding the devices and system will eleminate a difference in potential, thus eliminating (or controlling) the voltage.
Hope that makes sense. We may be in for another debate!
Hope that makes sense. We may be in for another debate!
i think under fault conditions when a heater shorts out or a pump connection gets exposed to water, or the lights fall into the tank etc a probe is useful as the fault current from the faulty appliance will go to ground down the probe and trip the gfci, if the probe wasnt there then you would be the path to ground when you put your hand in the tank, even though the gfci would trip youd get a nasty shock, providing of course the fault current exceeded the rating of the gfci, usually in north america its 5ma, admittedly its possible that any live stock could be injured or even killed under such circumstances, but rather them than me or the kids, its a difficult subject really to discuss properly because both arguments have merit, but water and electricity just dont mix so any connection to ground which would blow a gfci before you could potentially get a shock has got to be considered worthwhile, obviously a gfci would work without the probe by any inbalance between cores, and providing the house electrical system was in good working order and inspected regually there would be more chance of it working properly if tested regually and it wasnt a faulty unit, but poor electrical connections and bad continuity between ground connections then potentially theres danger, i mean how many of us know how safe our electrical installation systems are? i think if a probe is in place and has a confirmed continuity connection to a ground point and the gfci has been tested and confirmed as in working condition then as far as safety is concerned it got to be a good idea, however i can understand fish lovers dont want fault current killing their beloved livestock, i think theres a fine line between stray voltage or inductance which is relitively harmless and expected with electrical appliance under water and a fault current which can potentially kill, we dont know when we put our hands in the tank which is going to be there, unless we test with a meter every time we go near the tank, i think wed all agree this is impracticable, fault current doesnt smell, you cant see it or i doubt youd hear it either, so having the probe which will allow it to travel to ground and trip the circuit must be a good idea, the downside is that the tank electrical system, could by being dead, crash the system, hense the multiple gfci, if each appliance or 2-3 at most were on seperate units then only the fauly unit and maybe 1 or 2 other appliances would trip, this way something still stays on and the tank is ok, perhaps a good idea to to spread powerheads about on different gfci s and at least the live rock is still working, a bit long winded and no doubt still wrong in some eyes but i felt i had to say a bit more, i feel myself that this is a pretty good argument, im not going get into a heated debate but the thread seems to be going around a bit in circles now, so i thought id back 1 or 2 other views which have already been posted
Aquarist007
New member
I have my power heads connected to a battery back up system that would give about eight hours running time.
I also have 7 of the battery operated air pumps spread around the tanks, refugiums and sump areas.
Here's some data
Here's some data
Ya'll are still at it. I'm going to try to bring some data to this thread. It's long, but hopefully worth it..
Here's my standard mythbusters / jackass disclaimer... My work below involves intentionally energizing water with 120VAC. Don't try this at home
As I wrote before, I'm one of the few unfortunate that completely nuked a tank from a failed heater. There has been speculation in this thread (and elsewhere) that it wasn't electrocution, but probably pollution from the plating effect of submerged, live conductors that killed the stock. So tonight I got out my meter, a bucket of SW and a loose 120v cord and decided to replicate the conditions.
I stuck the cord into the tank, plugged it in. Nice buzzing sound, some little sparks, lots of electrolysis from the terminals, and little clouds of debris coming from terminals under the water. However at any two points, I could not get an AC voltage read of more than about .1VAC. This suggests to me that the energy in the tank was largely confined to the a path between the two terminals. I then spread the terminals out to 6+ inches. No difference. Preliminary conclusion: exposed equipment wiring will probably NOT electrocute the tank. Taken with my heater failure on a live tank and observations here, I will however claim that the pollution from energized copper terminals is substantial, and reached lethal levels in just a few hours (in my 24g tank).
Amperage draw from this scenario is not enough to trip a breaker (I'd only estimate an amp max, but my clamp meter was at work). I was surprised to see this result- I really thought there would be potential across different areas of the water. I suspect it was there, but was so noisy my meter couldn't detect (I saw a cool voltage mapping tool in my datacenter days that I really wish I had right now)...
This entire trial was run on a GFI protected circuit. As speculated in the thread, the GFI did NOT trip, because the current path flowed exclusively between the conductors submerged in the water.
I ran another trial with a ground inserted, approximately 10" from the exposed terminals. The GFI instantly tripped (and I mean instant, just like pushing the test button). This is the exact solution I am looking for in my tanks - GP + GFI interrupts the current flow upon fault of an electrical device. It took them both, and it was nice to empirically verify what I was trying to accomplish.
The next test will be to look at ground probe effectiveness as a function of distance to the fault. It's going to take more than a bucket of water for this- I'll have to wait to the next water change and I'll rig up something to test effectiveness equivalent to a sump (to help inform the multiple ground probe questions and speculation from this thread). I got some thoughts using a garden hose to simulate remote tanks.
I did not test ground probe / no GFI, as the GFI was there for my safety. But it would obviously introduce another current path, and nothing would be there to kill the circuit. From trial #1, this is obviously not good for the inhabitants (or the hobbyist).
Hope this helps, Chuck
Here's some data
Ya'll are still at it
. I'm going to try to bring some data to this thread. It's long, but hopefully worth it.. Here's my standard mythbusters / jackass disclaimer... My work below involves intentionally energizing water with 120VAC. Don't try this at home
As I wrote before, I'm one of the few unfortunate that completely nuked a tank from a failed heater. There has been speculation in this thread (and elsewhere) that it wasn't electrocution, but probably pollution from the plating effect of submerged, live conductors that killed the stock. So tonight I got out my meter, a bucket of SW and a loose 120v cord and decided to replicate the conditions.
I stuck the cord into the tank, plugged it in. Nice buzzing sound, some little sparks, lots of electrolysis from the terminals, and little clouds of debris coming from terminals under the water. However at any two points, I could not get an AC voltage read of more than about .1VAC. This suggests to me that the energy in the tank was largely confined to the a path between the two terminals. I then spread the terminals out to 6+ inches. No difference. Preliminary conclusion: exposed equipment wiring will probably NOT electrocute the tank. Taken with my heater failure on a live tank and observations here, I will however claim that the pollution from energized copper terminals is substantial, and reached lethal levels in just a few hours (in my 24g tank).
Amperage draw from this scenario is not enough to trip a breaker (I'd only estimate an amp max, but my clamp meter was at work). I was surprised to see this result- I really thought there would be potential across different areas of the water. I suspect it was there, but was so noisy my meter couldn't detect (I saw a cool voltage mapping tool in my datacenter days that I really wish I had right now)...
This entire trial was run on a GFI protected circuit. As speculated in the thread, the GFI did NOT trip, because the current path flowed exclusively between the conductors submerged in the water.
I ran another trial with a ground inserted, approximately 10" from the exposed terminals. The GFI instantly tripped (and I mean instant, just like pushing the test button). This is the exact solution I am looking for in my tanks - GP + GFI interrupts the current flow upon fault of an electrical device. It took them both, and it was nice to empirically verify what I was trying to accomplish.
The next test will be to look at ground probe effectiveness as a function of distance to the fault. It's going to take more than a bucket of water for this- I'll have to wait to the next water change and I'll rig up something to test effectiveness equivalent to a sump (to help inform the multiple ground probe questions and speculation from this thread). I got some thoughts using a garden hose to simulate remote tanks.
I did not test ground probe / no GFI, as the GFI was there for my safety. But it would obviously introduce another current path, and nothing would be there to kill the circuit. From trial #1, this is obviously not good for the inhabitants (or the hobbyist).
Hope this helps, Chuck
stricknine
New member
Brave, very brave!
...and unless you coat yourself in 1000V rated rubber eqip., and have someone on stand by with a fiberglass sheeps hook, I wouldnt suggest anymore trials! (it is milliamps that stop the heart) 
Im not going to try to theorize about what may have occurred electrically, but it is good to have confirmation that the theory put to the test was indeed confirmed. Also proven may be the signifigance of copper pollution!
Kudos.
...and unless you coat yourself in 1000V rated rubber eqip., and have someone on stand by with a fiberglass sheeps hook, I wouldnt suggest anymore trials!
(it is milliamps that stop the heart) Im not going to try to theorize about what may have occurred electrically, but it is good to have confirmation that the theory put to the test was indeed confirmed. Also proven may be the signifigance of copper pollution!
Kudos.
Re: Here's some data
Re: Here's some data
well you have proved a point, but please dont do it again, thankfully your ok and didnt get a shock however hopefully your test will calm tempers, not so much as here, but for future threads as well, can you please re-write the aricle when you have time with a little more detail and pm waterkeeper, he will be able to put it together a little better and hopefully we can then pass it around when questions are asked in the future
Re: Here's some data
<a href=showthread.php?s=&postid=14080391#post14080391 target=_blank>Originally posted</a> by cczarnik
Ya'll are still at it
Here's my standard mythbusters / jackass disclaimer... My work below involves intentionally energizing water with 120VAC. Don't try this at home
As I wrote before, I'm one of the few unfortunate that completely nuked a tank from a failed heater. There has been speculation in this thread (and elsewhere) that it wasn't electrocution, but probably pollution from the plating effect of submerged, live conductors that killed the stock. So tonight I got out my meter, a bucket of SW and a loose 120v cord and decided to replicate the conditions.
I stuck the cord into the tank, plugged it in. Nice buzzing sound, some little sparks, lots of electrolysis from the terminals, and little clouds of debris coming from terminals under the water. However at any two points, I could not get an AC voltage read of more than about .1VAC. This suggests to me that the energy in the tank was largely confined to the a path between the two terminals. I then spread the terminals out to 6+ inches. No difference. Preliminary conclusion: exposed equipment wiring will probably NOT electrocute the tank. Taken with my heater failure on a live tank and observations here, I will however claim that the pollution from energized copper terminals is substantial, and reached lethal levels in just a few hours (in my 24g tank).
Amperage draw from this scenario is not enough to trip a breaker (I'd only estimate an amp max, but my clamp meter was at work). I was surprised to see this result- I really thought there would be potential across different areas of the water. I suspect it was there, but was so noisy my meter couldn't detect (I saw a cool voltage mapping tool in my datacenter days that I really wish I had right now)...
This entire trial was run on a GFI protected circuit. As speculated in the thread, the GFI did NOT trip, because the current path flowed exclusively between the conductors submerged in the water.
I ran another trial with a ground inserted, approximately 10" from the exposed terminals. The GFI instantly tripped (and I mean instant, just like pushing the test button). This is the exact solution I am looking for in my tanks - GP + GFI interrupts the current flow upon fault of an electrical device. It took them both, and it was nice to empirically verify what I was trying to accomplish.
The next test will be to look at ground probe effectiveness as a function of distance to the fault. It's going to take more than a bucket of water for this- I'll have to wait to the next water change and I'll rig up something to test effectiveness equivalent to a sump (to help inform the multiple ground probe questions and speculation from this thread). I got some thoughts using a garden hose to simulate remote tanks.
I did not test ground probe / no GFI, as the GFI was there for my safety. But it would obviously introduce another current path, and nothing would be there to kill the circuit. From trial #1, this is obviously not good for the inhabitants (or the hobbyist).
Hope this helps, Chuck
well you have proved a point, but please dont do it again, thankfully your ok and didnt get a shock
however hopefully your test will calm tempers, not so much as here, but for future threads as well, can you please re-write the aricle when you have time with a little more detail and pm waterkeeper, he will be able to put it together a little better and hopefully we can then pass it around when questions are asked in the future
cczarnik, excellent contribution.
I gather from your evidence that the impedance of SW is significantly lower than that of animals, thereby protecting them as a conductive shield. One should be able to put their hand in there without a problem (just saying, of course)
This suggests this issue is no longer life or death anless something is out of the ordinary. To me this makes it easier to decide to use a ground probe and interrupter.
I gather from your evidence that the impedance of SW is significantly lower than that of animals, thereby protecting them as a conductive shield. One should be able to put their hand in there without a problem (just saying, of course
)This suggests this issue is no longer life or death anless something is out of the ordinary. To me this makes it easier to decide to use a ground probe and interrupter.
Appreciate the concerns for my safety guys- I'm comfortable with elecricity, I thought about this before I started tinkering- there is a reason I did it with a known good GFCI backing me up. Working with a live bucket of water is no different than working in a live panel (and I've done quite a bit of single phase and 3 phase electrical work in my datacenter days). I'm not sure I'm ready to conclude that the entire body of water was not energized- I have some thoughts on testing that, will do some more work tonight.
Aquarist007
New member
Does this explain this event:
About a year ago I had a clarkie that was on its way so I put him in my sump for a bit. Overnight he broke a glass heater(the last glass instrument I ran in a tank) and it tripped the breaker at the box.
I came down in the early morning ---reset the breaker---which it did---being dark in the sump I didn't notice the broken heater still on in the sump with the bare probes exposed. I put my hands in the sump water before I noticed the arcing. Never felt a thing.
And the clarkie was fine too
BTW
I was running the titanium probe
About a year ago I had a clarkie that was on its way so I put him in my sump for a bit. Overnight he broke a glass heater(the last glass instrument I ran in a tank) and it tripped the breaker at the box.
I came down in the early morning ---reset the breaker---which it did---being dark in the sump I didn't notice the broken heater still on in the sump with the bare probes exposed. I put my hands in the sump water before I noticed the arcing. Never felt a thing.
And the clarkie was fine too
BTW
I was running the titanium probe
Paul B
Premium Member
You never felt a thing because "you" were not gounded and you have more resistance than the water. The breaker would have tripped if the heater was closer to the probe. Salt water acted as a load just like a light bulb because it has resistance.
I also would assume that your ground probe was defective but I can't tell from here.
But if you decided to get a glass of water from the sink while your hand was in there with the broken heater, you would have a different respect for electricity.
If the current does not have any place to go it doesen't go anywhere. There are only two places current can go. To the neutral (or white wire) or to the ground. The neutral and ground are connected together in your panel but if you are using a GFCI breaker the neutral wire goes into the breaker before it goes to the neutral bar. This is not important for you to know.
As an electrician we normally work on live circuits and I can touch any live contact as long as no part of me is touching anything that is grounded which is why you diden't get a shock with your hand in the tank. See all those birds and squirrels standing on those live wires? They are completely safe as long as they don't touch a grounded object while they are there. Generally grounded things are not put near live high voltage circuits or you would see a lot of exploding birds and squirrels.
And they would explode completely leaving only some fur or feathers.
Almost all lighting circuits in cities now is 277 volts and the machinery is 480. It is much cheaper to wire a building like that because you can put more than twice as many lights on a circuit with the same size wire and copper wire is very expensive now.
It costs about as much as purple tangs
I also would assume that your ground probe was defective but I can't tell from here.
But if you decided to get a glass of water from the sink while your hand was in there with the broken heater, you would have a different respect for electricity.
If the current does not have any place to go it doesen't go anywhere. There are only two places current can go. To the neutral (or white wire) or to the ground. The neutral and ground are connected together in your panel but if you are using a GFCI breaker the neutral wire goes into the breaker before it goes to the neutral bar. This is not important for you to know.
As an electrician we normally work on live circuits and I can touch any live contact as long as no part of me is touching anything that is grounded which is why you diden't get a shock with your hand in the tank. See all those birds and squirrels standing on those live wires? They are completely safe as long as they don't touch a grounded object while they are there. Generally grounded things are not put near live high voltage circuits or you would see a lot of exploding birds and squirrels.
And they would explode completely leaving only some fur or feathers.
Almost all lighting circuits in cities now is 277 volts and the machinery is 480. It is much cheaper to wire a building like that because you can put more than twice as many lights on a circuit with the same size wire and copper wire is very expensive now.
It costs about as much as purple tangs
