GFCI 2-wire Experiment

[FionaZuppa]

i dont say this too often, its just one of those things i keep to myself, very obvious that many on this forum, including some mods, dont really understand electricity all that well.

here's an experiment showing you a possible scenario that a 2-wire GFCI will not protect you, and you are possibly dead.

the cord is a non-polarized nema 1- (i polarized it with silver marker). the hot has an inline ~18k resistor. the end of the cord has eyelets soldered on to attempt to mimic real terminations of an appliance. the sink is all plastic so no amps can flow out to a EGC, the water is warm tap water (my water is heavy in minerals and filtered via a water softener, more on this at the end). from the data, the "short" in the water (w/o the inline ohms) would not trip a 15 or 20A OCPD and the GFCI is as happy as a virgin for the 1st time. the stray amps across the unattached amp probes in random location in the water indicates that amps will still flow from wire --> across water --> into the body --> through body --> back into water, and return back to wire !! so as much as some of you think amps only take path of least resistance (WRONG), it takes all paths.

i dont care to explain this elementary experiment, so you'll need to understand it for yourself. in this experiment the amps through the unattached probes would not have been enough to kill, but the scenario shows the possibility exists.


voltage across end of wire no-load

short circuit amps

wires ends in water

amps of wire in water

amps probes just in water, not attached to anything

amps flowing through the unattached amp probes

shortest distance between the ends of the wire

as for water chemistry, the cleaner the water the more hazard there is. and depending on how the end of the wire terminates into the item, stray amps will vary (the closer the connections are to each other the less stray amps, the farther apart and bigger the connection then more stray amps).

hence, the reason why 2-wire GFCI does not cover all hazards, some potentially deadly. hence, the reason why all GFCI should be 3-wire. hence, the reason why all "bathroom" appliance should be NEMA 5- !!!

 

[K8MHZ]

hence, the reason why 2-wire GFCI does not cover all hazards, some potentially deadly. hence, the reason why all GFCI should be 3-wire. hence, the reason why all "bathroom" appliance should be NEMA 5- !!!

Can you repeat the experiment using a grounded GFCI and let us see the difference it makes?

 

[FionaZuppa]

Can you repeat the experiment using a grounded GFCI and let us see the difference it makes?

i can, but 1st you can explain why you want me to use a 5- cap cord and my 5- GFCI w/ EGC. my experiment was using GFCI w/ EGC.
i am not sure you understood the results of the crude experiment.
(just to note, the amp readings in experiment are all mA)

you need to ask yourself, in all the text before 1st pic, what is the most important piece of information ???

 

[K8MHZ]

i can, but 1st you can explain why you want me to use a 5- cap cord and my 5- GFCI w/ EGC.
i am not sure you understood the results of the crude experiment.

I am pretty sure I understand your experiment a little more than you think.

You assert that using a grounded circuit is safer than a non-grounded one and have only provided current measurements for one. To compare the two and to say one is better or safer than the other, both types must be tested using the same parameters.

Also note that a GFCI doesn't protect from line to neutral faults. Only line to ground.

When you get done testing two unloaded leads in the water, put the 18,000 ohm resistor across the hot and neutral where a real load would be. If I read your set up correctly, the 18k resistor was placed in series in the hot lead.

 

[FionaZuppa]

I am pretty sure I understand your experiment a little more than you think.

You assert that using a grounded circuit is safer than a non-grounded one and have only provided current measurements for one. To compare the two and to say one is better or safer than the other, both types must be tested using the same parameters.

Also note that a GFCI doesn't protect from line to neutral faults. Only line to ground.

When you get done testing two unloaded leads in the water, put the 18,000 ohm resistor across the hot and neutral where a real load would be. If I read your set up correctly, the 18k resistor was placed in series in the hot lead.

WRONG, sorry, i not trying to be mean or anything, you dont understand it. i dont need to show what 5- cap cord and GFCI w/ EGC would do, i only need to show the hazard.
lets start with the basic Q, can you tell us all why i placed a 18k inline?? or lets make it a simpler Q, why did i put an inline resistor there??

 

[K8MHZ]

you need to ask yourself, in all the text before 1st pic, what is the most important piece of information ???

I already did. I asked myself why you would think an 18k resistor in line with the hot and not across the two leads would mimic an appliance. Since the impedance of your meter is much higher than the resistor, you may as well have tossed an live extension cord into the water.

I also asked myself how the information gleaned can be directly related to the protection of personnel.

As for the pics, I don't see much to get worried about. Now if you read 6.7 amps instead of milliamps that would be different.

 

[K8MHZ]

WRONG, sorry, i not trying to be mean or anything, you dont understand it. i dont need to show what 5- cap cord and GFCI w/ EGC would do, i only need to show the hazard.
lets start with the basic Q, can you tell us all why i placed a 18k inline??

I think you need to tell us, because it's not needed. Bypass it and retest. Your results shouldn't change much with a high Z meter like you have.

 

[FionaZuppa]

I already did. I asked myself why you would think an 18k resistor in line with the hot and not across the two leads would mimic an appliance. Since the impedance of your meter is much higher than the resistor, you may as well have tossed an live extension cord into the water.

I also asked myself how the information gleaned can be directly related to the protection of personnel.

As for the pics, I don't see much to get worried about. Now if you read 6.7 amps instead of milliamps that would be different.

again, sorry, not trying to be mean, perhaps you need to watch from the sidelines on this one. re-read the experiment and maybe (maybe) you'll understand what it says, and why there is an inline resistor there. you'll need to use some math to extrapolate out some real data, of which i have already explained in words.

I think you need to tell us, because it's not needed. Bypass it and retest. Your results shouldn't change much with a high Z meter like you have.

nah, you try it your way. you perhaps missed the part that this was an experiment (a safe experiment). good luck with yours, hopefully there will be someone close by in case your experiment bites you.

 

[K8MHZ]

I am not trying to be mean, either, but I really don't think you know how to set up an experiment that proves your assertion. That is why I am asking for further measurements.

All I am asking from you is nothing more than what I would have been asked if I set up the same experiment and showed it to my instructors.

 

[FionaZuppa]

I am not trying to be mean, either, but I really don't think you know how to set up an experiment that proves your assertion. That is why I am asking for further measurements.

All I am asking from you is nothing more than what I would have been asked if I set up the same experiment and showed it to my instructors.

have at it, post what you get. if you understood my experiment the way it is set up you would not be asking the questions you are asking :thumbsup:

 

[K8MHZ]

again, sorry, not trying to be mean, perhaps you need to watch from the sidelines on this one. re-read the experiment and maybe (maybe) you'll understand what it says, and why there is an inline resistor there. you'll need to use some math to extrapolate out some real data, of which i have already explained in words.

One test measurement trumps pages of math every time.

Please, bypass the resistor and test again using the same meter on the same setting.

 

[K8MHZ]

have at it, post what you get.

Why me? It's your experiment and it's you that has had your data questioned. To me, a refusal to comply with my very simple requests tells me you don't want to really learn, you just want to dictate.

 

[FionaZuppa]

Why me? It's your experiment and it's you that has had your data questioned. To me, a refusal to comply with my very simple requests tells me you don't want to really learn, you just want to dictate.

why you? because its you who insists on testing your way. i am not testing it your way, you can test it your way, so get cracking, prove something to us.

 

[480sparky]

 

[ATSman]

I am pretty sure I understand your experiment a little more than you think.

You assert that using a grounded circuit is safer than a non-grounded one and have only provided current measurements for one. To compare the two and to say one is better or safer than the other, both types must be tested using the same parameters.

Also note that a GFCI doesn't protect from line to neutral faults. Only line to ground.

When you get done testing two unloaded leads in the water, put the 18,000 ohm resistor across the hot and neutral where a real load would be. If I read your set up correctly, the 18k resistor was placed in series in the hot lead.

This is the key point to the argument; he is not measuring ground current that a GFCI is designed to monitor and interrupt! :slaphead:

 

[FionaZuppa]

This is the key point to the argument; he is not measuring ground current that a GFCI is designed to monitor and interrupt! :slaphead:

hey now, no helping. :thumbsup:

lots was missed by the questioner. i can give another hint for the questioner, THERE IS NO LOAD ATTACHED TO THE WIRES (SCENARIO) !!!!

 

[K8MHZ]

why you? because its you who insists on testing your way. i am not testing it your way, you can test it your way, so get cracking, prove something to us.

OK, here's the deal.

Your experiment shows absolutely nothing of importance.

Since your sink is not grounded by virtue of it's material, any current passing through the water will be line to neutral, not line to ground.

Your high Z tester will be blind to an 18k resistor for the most part. I just wanted to show you that. Your experiment will be nearly the same without it, but you believe what you want to believe.

And most of all, the current in the water from line to neutral is not a hazard to life so long as that life is not a path to ground. I know this is true.

How to I know this is true?

Well, one day I heard a noise and looked over to see that something had fallen on our fish aquarium and it knocked the light into the water. The bulb stayed on. There was one fish in the tank and it was fine. It took me a couple seconds (seemed like minutes) to un plug the light. I pulled it out of the water and checked on the fish. No injuries whatsoever. The aquarium was glass and none of the metal parts were grounded.

All you have shown us is that your water will pass a bit over 6 amps when in series with an 18k resistor. You have not demonstrated any hazard, nor have given us any information that would prove the GFCI would have tripped if there was an EGC.

 

[GoldDigger]

All you have shown us is that your water will pass a bit over 6 amps when in series with an 18k resistor. You have not demonstrated any hazard, nor have given us any information that would prove the GFCI would have tripped if there was an EGC.

You are suggesting that he is using a 108kV source?

The meter reading is much more likely to be ma, not A.

 

[FionaZuppa]

OK, here's the deal.

Your experiment shows absolutely nothing of importance.

Since your sink is not grounded by virtue of it's material, any current passing through the water will be line to neutral, not line to ground.

Your high Z tester will be blind to an 18k resistor for the most part. I just wanted to show you that. Your experiment will be nearly the same without it, but you believe what you want to believe.

And most of all, the current in the water from line to neutral is not a hazard to life so long as that life is not a path to ground. I know this is true.

How to I know this is true?

Well, one day I heard a noise and looked over to see that something had fallen on our fish aquarium and it knocked the light into the water. The bulb stayed on. There was one fish in the tank and it was fine. It took me a couple seconds (seemed like minutes) to un plug the light. I pulled it out of the water and checked on the fish. No injuries whatsoever. The aquarium was glass and none of the metal parts were grounded.

All you have shown us is that your water will pass a bit over 6 amps when in series with an 18k resistor. You have not demonstrated any hazard, nor have given us any information that would prove the GFCI would have tripped if there was an EGC.

yikes, yikes, and yikes again.
my hi Z Fluje is blind to 18k resistor, how so, please enlighten us.

the part in red, really? c'mon. just so i am clear, you are talking about EGC and not the grounded CCC, yes? if so then back to basics-101 for you.

the part in pink, really? c'mon. rip out your calculator or whatever handy-dandy tool you have, do some math.

 

[K8MHZ]

hey now, no helping. :thumbsup:

lots was missed by the questioner. i can give another hint for the questioner, THERE IS NO LOAD ATTACHED TO THE WIRES (SCENARIO) !!!!

So what?

Nothing you have done has proved this:

hence, the reason why 2-wire GFCI does not cover all hazards, some potentially deadly. hence, the reason why all GFCI should be 3-wire. hence, the reason why all "bathroom" appliance should be NEMA 5- !!!