GFCI and related

[jnb]

I am getting a handle on certain issues that I want to understand so answers to these questions would be helpful?

1) if a 100v power head is leaking electricity because the wires insultation has a crack - why is the stray voltage often less than 100 Volts?

2) If a 100 volt powerhead is indeed leaking electrcity into the water lets say 10 volts and I have gound probes installed - then there is current flowing thru the tank - are the fish, etc feeling this current or are they ok?

3) if a 100 volt powerhead is indeed leaking electricity in to the water and I have ground probes installed - and I go into the tank with my hands but I am standing on rubber or otherwise am not becoming a better ground than the ground probes, am I ok?

4) if a 100 volt powerhead is indeed leaking electricity in to the water and I DO NOT have ground probes installed - and I go into the tank with my hands but I am standing on rubber or otherwise am not becoming a better ground than the ground probes, am I ok?

5) if a 100 volt powerhead is indeed leaking electricity in to the water and I DO NOT have ground probes installed - and I go into the tank with my hands but I am NOT standing on rubber or otherwise I am barefoot and standing on a tile floor , am I ok?

6) if a 100 volt powerhead is indeed leaking electricity in to the water and I DO NOT have ground probes installed on that powerhead but I do have GFCI installed on that powerhead - and I go into the tank with my hands but I am standing on rubber , will the GFCI trip?

7) if a 100 volt powerhead is indeed leaking electricity in to the water and I DO NOT have ground probes installed on that powerhead but I do have GFCI installed on that powerhead - and I go into the tank with my hands but I am standing barefoot on a tile floor , will the GFCI trip?

8) If I have GFCI's installed one each on three pieces of equipment and one GFCI trips, in theory, will they all trip?

 

[BeanAnimal]

Re: GFCI and related

<a href=showthread.php?s=&postid=13617126#post13617126 target=_blank>Originally posted</a> by jnb
I am getting a handle on certain issues that I want to understand so answers to these questions would be helpful?

1) if a 100v power head is leaking electricity because the wires insultation has a crack - why is the stray voltage often less than 100 Volts?

The wire may not be fully exposed. This means that there is resistance. The saltwater also has resistance. A quick look at Ohm's law will help you understand

2) If a 100 volt powerhead is indeed leaking electrcity into the water lets say 10 volts and I have gound probes installed - then there is current flowing thru the tank - are the fish, etc feeling this current or are they ok?

That depends on A LOT of factors. How much current flows dependson the resistance between the leak and the ground probe. The current through the livestock depends on the resistance of the livestock and the path in which the current flows through the tank. I.E. the fish may not be in the path of current, and the current may or may not flow through the fish. The GFCI will take care of the problem by tripping and stopping the current flow.

3) if a 100 volt powerhead is indeed leaking electricity in to the water and I have ground probes installed - and I go into the tank with my hands but I am standing on rubber or otherwise am not becoming a better ground than the ground probes, am I ok?

In theory yes. But a GFCI would make you safer by eliminating the chance that you DO create a deadly circuit with your body.

4) if a 100 volt powerhead is indeed leaking electricity in to the water and I DO NOT have ground probes installed - and I go into the tank with my hands but I am standing on rubber or otherwise am not becoming a better ground than the ground probes, am I ok?

Your question makes no sense, how can you not be a better ground if there IS NO ground probe? Anyway, you are in more danger under most scenarios, as you are a good candidate to become the ground probe, because there is none. A GFCI will fix this issue as well.

5) if a 100 volt powerhead is indeed leaking electricity in to the water and I DO NOT have ground probes installed - and I go into the tank with my hands but I am NOT standing on rubber or otherwise I am barefoot and standing on a tile floor , am I ok?

You become the ground probe. You have a good chance of getting shocked or electrocuted. A GFCI takes care of this too.

6) if a 100 volt powerhead is indeed leaking electricity in to the water and I DO NOT have ground probes installed on that powerhead but I do have GFCI installed on that powerhead - and I go into the tank with my hands but I am standing on rubber , will the GFCI trip?

No it will not trip. The current does not flow anywhere. That is what the ground prope is for. It would have caused the GFCI to trip before you put your hands in the tank.

7) if a 100 volt powerhead is indeed leaking electricity in to the water and I DO NOT have ground probes installed on that powerhead but I do have GFCI installed on that powerhead - and I go into the tank with my hands but I am standing barefoot on a tile floor , will the GFCI trip?

Yes the GFCI will trip.

8) If I have GFCI's installed one each on three pieces of equipment and one GFCI trips, in theory, will they all trip?

No they will not all trip, only the GFCI that senses current missing on the Neutral leg.

 

[BeanAnimal]

You let out several scenarios.

If you have a PROBE and NO GFCI and you have a reflector that has become energized, touching the reflector and the water creates a circuit between the REFLECTOR --> YOU ---> PROBE. Deadly.

A ground probe should not be used without GFCI protection on all tank connected equipment.

 

[das75]

jnb, get the mantra (get a GFI)? How many $10 devices can save your life.

 

[jnb]

thanks - I was hoping you would be the one to answer - I had read many of the GFCI post you contributed too - and the last point you made here was indeed noted

you said all tank connected equipment - I was thinking my 12 v tunze's would not need this and was thinking my external ehiem pump may not be much of a risk (as long as the power cord to the ehiem is kept away from water exposure - the risk being that it develope an internal crack which I thought may be remote.

may have more questions as I get my system tweaked for appliance leakage.

<a href=showthread.php?s=&postid=13617290#post13617290 target=_blank>Originally posted</a> by BeanAnimal
You let out several scenarios.

If you have a PROBE and NO GFCI and you have a reflector that has become energized, touching the reflector and the water creates a circuit between the REFLECTOR --> YOU ---> PROBE. Deadly.

A ground probe should not be used without GFCI protection on all tank connected equipment.

 

[BeanAnimal]

Put important items on their own GFCIs. Use a ground probe if you like. Test the GFCIs on fairly regular basis.

 

[jnb]

not sure what you are saying here - is mantra a device? I did not have GFCI's. I had ground probes without GFCI's which I understand now can be very dangerous. Got smarter lately and made a couple of leviton wall receptacles up in their own portable boxes, etc to selectively separately make the appliance safe and here just getting a handle on how it all works - and tested my water for leakage (2 volts but need to do it with the heaters on) so if mantra is the intangible thing and you are saying get GFCI's I hear you and am - thanks

btw = more than 10$

ps I believe marine depot and the like should not sell ground probes with informing the public and dangers with GFCI.

<a href=showthread.php?s=&postid=13617656#post13617656 target=_blank>Originally posted</a> by das75
jnb, get the mantra (get a GFI)? How many $10 devices can save your life.

 

[BeanAnimal]

mantra - A sacred verbal formula repeated in prayer... (Hindu I think)

Used in common speach to mean "you get the idea" when somebody repeats the same theme over and over

 

[Budgeon]

not sure if this will help however, why doesn't a bird get fried when sitting on a wire? well the answer is simple. The bird is not grounded it becomes "part" of the circuit so there is no danger to the bird. Just as if you were standing on a rubber mat (in insulator) you'll become part of the circuit fi there might be bleeding of electricity in your tank however, the problem comes when there is a path to ground that has less resistance than you (electricity seeks the path of least resistance) if you supply a ground probe in your tank it supposedly reduces the risk of shock and hurting the inhabitants. A GFCI is a good thing to have b/c it measures the difference in potential between the hot wire (black) and the grounded wire (white neutral ) ( don't mistake grounding wire green). Oh and if you have all those problems in your tank throw those dam things out and buy new ones hahaha. good questions though

 

[BeanAnimal]

<a href=showthread.php?s=&postid=13617867#post13617867 target=_blank>Originally posted</a> by Budgeon
not sure if this will help however, why doesn't a bird get fried when sitting on a wire? well the answer is simple. The bird is not grounded it becomes "part" of the circuit so there is no danger to the bird.

Well sort of. Current passes through the bird. He has two legs and his body has resistance between those two legs. The feet touch the wire at some distance. The wire also has resistance. So the bird is a parallel resistor IN the circuit. You can calculate the current through its body using ohms law.

when there is a path to ground that has less resistance than you (electricity seeks the path of least resistance)

Again, sort of. Electricity seeks all paths to ground You can still get shocked even IF the ground probe has a better path to ground.

 

[jnb]

viscosity - when you are told to fill up a test tube up to a specific mark - do you do so using the bottom of the curve or the top level? or middle ground - I can not believe my new red sea pro salt appears to have an alk of 5 dkh - is it possible that the white crust remains of my usual mixing can has eaten up measurable alk? - it has been mixing for 30 hrs now while I got salinity just right

 

[BeanAnimal]

You measure from the bottom of the maniscus