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Me too! then my wallet!
GFI Receptacle or Grounding Probe?
- Thread starter rdnelson
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does this solve the problem of getting shocked, i'll be shutting down all power into the tank while working in it, i can operate everything individually.
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Just curious, I know that homes have been burnt down, but are there any deaths on record from electrocution from aquarium hobby equipment? I mean, 110v is no fun, but you generally get over it.
To answer both your statement and grouper's question, yes I believe the salt water tank is acting as a quasi battery. Do I think I still have stray voltage in my tank? I would assume so but I have now created a direct path to a good grounding source. Before I get bombarded with do I think this is a good thing, an argument can be made pro and con. I personally am very big on grounding.
A question to Rich, do you see any validity to my theory of Arc fault vs gfci with the issue of stray voltage in our tanks?
I do agree that we have salt water systems that are quite susceptible to inductive current. Not sure about the harmonic distortion thing, do we have any GT PhD grads in electrical engineering whose thesis was on harmonics?
Not sure the Arc Fault will do much if I correctly understand how they work. From what I have learned about them they are designed to sense the frequencies and/or current patterns that are created as a result of an arc (spark). Bleeding voltage would not generate that signature in my estimation. But that is complete speculation on my part.
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I don't have anything in my fish room or tank that isn't run on a GFCI. It isn't worth the risk to me. I have three 20 amp circuits in my fish room. Each has a shutoff switch and the GFCI with monitor LED mounted in 3 boxes on one wall away from the water. All outlets in the room are daisy chained through these 3 CFGI outlets protecting all outlets in the room. I can easily cut the power to a circuit (using the switch on the wall) and see if the power is on by looking at the LED on the GFCI.
The only time a GFCI has tripped was due to a leaking submerged pump or heater. In the 7 years since I set this up, the GFCI has tripped only a handful of times. I don't think it is worth worrying about them tripping when you are away because in my experience, it doesn't happen all that often.
Assuming you are using GFCIs on all your circuits, a grounding probe can do no harm, only good. No harm since if stray current is flowing (as in rdnelson's original post) the GFCI will trip. The good is that the GFCI will trip right away as opposed to waiting until you put your hand in the tank and using your body as a path.
I think wall outlet GFCIs are better (more convenient) as you can monitor their state and reset them without going to the breaker panel.
Another idea is instead of using a single GFCI and using the load lugs (as I did), you can install a separate GFCI at each outlet location in your fish room to limit the number of items that will lose power when one trips. The drawback if this is you may not be able to easily tell the status of all the GFCIs.
Finally, use an Neptune Systems Apex to monitor power to the circuits. Build an Apex system with at least one EB4 or EB8 for each circuit. When the power to one of the circuits fails, you can program the Apex to send you an email.
The only time a GFCI has tripped was due to a leaking submerged pump or heater. In the 7 years since I set this up, the GFCI has tripped only a handful of times. I don't think it is worth worrying about them tripping when you are away because in my experience, it doesn't happen all that often.
Assuming you are using GFCIs on all your circuits, a grounding probe can do no harm, only good. No harm since if stray current is flowing (as in rdnelson's original post) the GFCI will trip. The good is that the GFCI will trip right away as opposed to waiting until you put your hand in the tank and using your body as a path.
I think wall outlet GFCIs are better (more convenient) as you can monitor their state and reset them without going to the breaker panel.
Another idea is instead of using a single GFCI and using the load lugs (as I did), you can install a separate GFCI at each outlet location in your fish room to limit the number of items that will lose power when one trips. The drawback if this is you may not be able to easily tell the status of all the GFCIs.
Finally, use an Neptune Systems Apex to monitor power to the circuits. Build an Apex system with at least one EB4 or EB8 for each circuit. When the power to one of the circuits fails, you can program the Apex to send you an email.
I am sure Bill will disagree with me but I believe it can do harm even if you have GFIs. Here is why I feel that way.
1. With multiple paths to ground some current will flow through each in the event of a ground fault. How much ? It depends on the resistance of those ground paths. Should enough flow through the ground probe the GFI will not operate.
2. Depending on we're the ground connection of the probe is made, a difference of potential between the probe and the receptacle ground could exist. In an effort to equalize the two current will flow between them just like air moving from a high pressure system to a low pressure system. So by trying to fix a problem you actually create one were they wasn't one before.
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I buy it 100%. Basic physics.
Schwaggs;813734 wrote: I'm not buying it.
1) If the current is so low as to not trip the GFCI, I suspect it isn't high enough to hurt anything anyway.
2) Seriously... :roll: I think your stretching...
I didn't say that the current was so low as to not trip the GFI. I said it would be split between the two ground paths thereby lowering the amount seen by the GFI and therefore the GFI may not trip. If the resistance of the the two paths are equal, the current split will be 50-50. But if the resistance of the ground probe is substantially lower than the one through the receptacle the bulk of the current will flow through the ground probe. It is a proven fact when dealing with parallel circuits. If you like, I can find a text book on it for you. So how would that be a problem? It may not be a problem for you and I other than we might feel a tingle but the livestock would be much more susceptible to it.
A quick search on Google brings this up as one result. I have not read it but it appears to explain it correctly and uses Ohms Law correctly.
Rich I understand your point on multiple paths to ground and it does bring up the question of what will be the shortest path to ground especially if the grounding probe is a type with a cord cap that only has the grounding prong wired. The question of whether enough potential current is carried away by the ground probe that would interfere with the functioning of a gfi has my curiosity and believe I will run a couple tests this weekend. I have a brother coming up from Augusta area who is a retired electrical instrumentation expert that I'm sure when I present this thread to him will be more than happy to lend his expertise too.
By the way I have a nice large rock of neon green paly with your name on it and as a bonus it has some lovely dark green patches of bryopsis that really helps accentuate the neon palys. Just let me know when you want to meet up and will bring it to you
By the way I have a nice large rock of neon green paly with your name on it and as a bonus it has some lovely dark green patches of bryopsis that really helps accentuate the neon palys. Just let me know when you want to meet up and will bring it to you
Most everything electrically can be explained using the more tangible (and far less dangerous) parallell of water. Something that none of us are not too familiar with. I will see if I can type this so it is intelligible.
Lets say you 3 flow meters monitoring your flow to and from your sump. You have 2 drains of which one is set lower in the tank than the second. The primary we shall call neutral, and the back up we shall call ground. In this theory neutral should be the only one used constantly and "Ground" is only there if there is a problem with "neutral"
Flow meter #3 is connected to the return pump line. The computer monitoring these 3 devices is constantly checking to make sure the sum of flow from meter #1 (neutral) is within a tolerance of flow meter #3 (Hot). Should flow meter #2 have any considerable flow at all the computer will set an alarm (trip the GFCI). Also if flow between #1 and #3 are out of a small percentage of error it will also set an alarm (trip GFCI). In this equation there is not necessarily any flow in #2 "ground" but something is not right and the computer picks up on this variation. It may not know that your tank has sprung a leak, but it knows that #1 and #3 have too much variation for things to be right.
Now to the current theory, a ground probe and GFI could split the difference in the out of speck difference between #1 and #3. Lets say you have a small amount of water running down a drain on a separate system of a flow meter. This is un-accounted for in the computer's programming and is paralleled to the faulty equipment being wired to a separate GFCI than that which the ground probe is plugged into. In this scenario both an alternate "emergency drain (ground)" and the one on your original system are getting a trickle but still within a margin of error pre-programmed. Had there not been an alternate path the flow rate in your emergency drain would have tripped flow meter #2 causing an alarm. Just because you have split your problem of unmatched flow between 2 sources does not mean that the problem is not as large as the sum of their parts.
Now since your GFCI is neglecting %50 of your leaking voltage you feel it is safe to go stick your hand in the system with wet socks on a wet floor. :confused2: :doh:
Lets say you 3 flow meters monitoring your flow to and from your sump. You have 2 drains of which one is set lower in the tank than the second. The primary we shall call neutral, and the back up we shall call ground. In this theory neutral should be the only one used constantly and "Ground" is only there if there is a problem with "neutral"
Flow meter #3 is connected to the return pump line. The computer monitoring these 3 devices is constantly checking to make sure the sum of flow from meter #1 (neutral) is within a tolerance of flow meter #3 (Hot). Should flow meter #2 have any considerable flow at all the computer will set an alarm (trip the GFCI). Also if flow between #1 and #3 are out of a small percentage of error it will also set an alarm (trip GFCI). In this equation there is not necessarily any flow in #2 "ground" but something is not right and the computer picks up on this variation. It may not know that your tank has sprung a leak, but it knows that #1 and #3 have too much variation for things to be right.
Now to the current theory, a ground probe and GFI could split the difference in the out of speck difference between #1 and #3. Lets say you have a small amount of water running down a drain on a separate system of a flow meter. This is un-accounted for in the computer's programming and is paralleled to the faulty equipment being wired to a separate GFCI than that which the ground probe is plugged into. In this scenario both an alternate "emergency drain (ground)" and the one on your original system are getting a trickle but still within a margin of error pre-programmed. Had there not been an alternate path the flow rate in your emergency drain would have tripped flow meter #2 causing an alarm. Just because you have split your problem of unmatched flow between 2 sources does not mean that the problem is not as large as the sum of their parts.
Now since your GFCI is neglecting %50 of your leaking voltage you feel it is safe to go stick your hand in the system with wet socks on a wet floor.
:confused2: :doh:kayakATL;813776 wrote: Most everything electrically can be explained using the more tangible (and far less dangerous) parallell of water. Something that none of us are not too familiar with. I will see if I can type this so it is intelligible.
Lets say you 3 flow meters monitoring your flow to and from your sump. You have 2 drains of which one is set lower in the tank than the second. The primary we shall call neutral, and the back up we shall call ground. In this theory neutral should be the only one used constantly and "Ground" is only there if there is a problem with "neutral"
Flow meter #3 is connected to the return pump line. The computer monitoring these 3 devices is constantly checking to make sure the sum of flow from meter #1 (neutral) is within a tolerance of flow meter #3 (Hot). Should flow meter #2 have any considerable flow at all the computer will set an alarm (trip the GFCI). Also if flow between #1 and #3 are out of a small percentage of error it will also set an alarm (trip GFCI). In this equation there is not necessarily any flow in #2 "ground" but something is not right and the computer picks up on this variation. It may not know that your tank has sprung a leak, but it knows that #1 and #3 have too much variation for things to be right.
Now to the current theory, a ground probe and GFI could split the difference in the out of speck difference between #1 and #3. Lets say you have a small amount of water running down a drain on a separate system of a flow meter. This is un-accounted for in the computer's programming and is paralleled to the faulty equipment being wired to a separate GFCI than that which the ground probe is plugged into. In this scenario both an alternate "emergency drain (ground)" and the one on your original system are getting a trickle but still within a margin of error pre-programmed. Had there not been an alternate path the flow rate in your emergency drain would have tripped flow meter #2 causing an alarm. Just because you have split your problem of unmatched flow between 2 sources does not mean that the problem is not as large as the sum of their parts.
Now since your GFCI is neglecting %50 of your leaking voltage you feel it is safe to go stick your hand in the system with wet socks on a wet floor.
One of the few times a water analogy actually works well. Good job.
. In theory the fact that there is less flow on one meter then the other (unbalanced current from hot to neutral) the computer should go into alarm (GFI trip). However as you point out it could be within tolerance.rdnelson99;813797 wrote: One of the few times a water analogy actually works well. Good job.
Thanks! I have had to use the analogy many a time to teach or explain current, voltage, and resistance. Still have not figured out how to explain AC and DC with out drawing oscilloscope like drawings. Ill get back to you when i find the water analogy for that one.
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Piece of cake. The ocean has waves right? They are generally shaped like the sine wave. LOL. I thought I knew this stuff until I taught second year apprentices (that is when all the math, chemistry and theory kick in). Most of the class had GEDs and had never had any algebra, trigonometry or chemistry. You find out just how much you DON'T know when you teach.
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