GFI receptacles

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roger said:
The onboard test button will work on a GFCI with out an EGC present.

Roger
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I'll take your word on that. Upon reflection, it would be possible to create the imbalance by routing the current flow from the ungrounded (hot) through the sensing device, then back to the grounded (neutral) without going back through the sensors.
But a plug-in tester can't bypass the sensor, and without a ground, it can't create an imbalance.
 
You are correct that an external indicator (tester) will not operate the GFCI with out an EGC present but, to see how the onboard test button woks click HERE.

The resistor circuit simulates the imbalance.

Roger
 
quogueelectric said:
You obviously haven’t tested this yourself.
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And I also have not seen your “test plan.” You know, this is the document that describes your test methodology, the required test equipment, the measurements to be taken, the expected results, and the manner of interpreting the results. So why don’t you just post a link to a copy of your test plan and the report from the test lab?

The simple statement, “I did a test” will gain you no credibility. A test has no meaning unless it is repeatable by anyone who wishes to attempt to conduct the same test independently. That is, the test, or experiment, must be documented in a clear and comprehensive manner, so that someone can go to a lab, do the same test in the same manner, and obtain the same results.

I suspect that there were significant errors in your test methodology. But I cannot confirm that suspicion without reviewing your process. In the mean time, please be more polite in your communications with other members of this Forum.
 
test plan

test plan

Here is my test plan
{ I went to college for electronics and learned electricity a little differently from most electricians I learned differently so I always walked to the beat of a different drum. When I was a young foreman I was a real runner I was working in a precast slab parking garage where I was helping annother foreman install the lighting at a hospital .
The temp was all run from the basement and the water poured in every time it rained all the way to the basement. The temp kept tripping and production went to zero.
I in my infinite wisdom rigged an extenion cord with alligator clips to a gfci receptacle like a little jump box to clip on to the temp lighting circuit which was not on gfi my helper started hammerdrilling into the concrete and before long he said " I just got a shock" I of course told him he was an idiot and that it was impossible because he was on a gfci ckt.
He went back to work in a little while I heard a shriek and the Hilti gun went flying past my head. He said I got annother shock we were now about to do battle. I said give me the drill and I charged up the ladder and began drilling soaking wet clothes ladder one hand on the concrete to show him it was impossible and WHAMMO I got BLASTED on my gfi receptacle where I had all the theory in the word to tell me this wouldnt happen.
It was impossible I have at least a half dozen experts on this board telling me it is not possible the 2 conductors were surrounded by equal and opposite currents thru the ct WHAMMO.
To make a long story short I found that when I connected the ground the gfi tripped without a painful shock and I could quickly go back and reset it and give him 350+ feet of pipe and 14 hid wallpacks a day because my boss did not care how I did it he just wantd to know how many lights I got up each day.}
This my friends is a REAL LIFE EXPERIENCE not some engineer hiding behind his books telling me it is not possible. I am answering a direct response from the original poster and if you read my post I said that this was IN MY EXPERIENCE not yours.
They told Columbus the world was flat didnt they and all the sheep believed in that. This was about 15 years ago and maybe the technology has changed since then. So I should try to be more polite about my posts sure I will you have all been so polite yourselves. I apologize for not thinking exactly as you do.
 
Well qu, who ever said a GFCI will prevent you from getting shocked?

Where did you get your belief that a GFCI will prevent a shock?

A GFCI whether connected to an EGC or not will not prevent a shock, you have been believing a falsehood

Your test doesn't hold much weight and was an example of not understanding the situation at hand.

As far as being polite, it seems as though every time you make a post that is questioned or pointed out to be in err you respond in a defensive and at times in a rude manner.

If you are going to continue to participate here be assured you will be called on your claims and statements and corrected by other members when you are wrong. It would behoove you to learn from these situations and say thanks for the enlightenment instead of thinking you are being mistreated in some way.

Roger
 
I got lost after the alligator clips part. You put alligator clips on an extension cord so you could clip into the temp lights, which weren't GFI'd? No offense, but that's not what I would call 'infinite wisdom'. Testing and replacing/repairing the cords and tools should have come first.
Then you state the circuit is GFI'd. I'm confused at this point.
 
You as well as I

You as well as I

roger said:
Well qu, who ever said a GFCI will prevent you from getting shocked?

Where did you get your belief that a GFCI will prevent a shock?

A GFCI whether connected to an EGC or not will not prevent a shock, you have been believing a falsehood

Your test doesn't hold much weight and was an example of not understanding the situation at hand.

As far as being polite, it seems as though every time you make a post that is questioned or pointed out to be in err you respond in a defensive and at times in a rude manner.

If you are going to continue to participate here be assured you will be called on your claims and statements and corrected by other members when you are wrong. It would behoove you to learn from these situations and say thanks for the enlightenment instead of thinking you are being mistreated in some way.

Roger
Click to expand...
Are entitled to your opinion. I was taught that a gfci will trip within 1/2 cycle and will trip at a threshold of .005 amps which I was also taught to be not a painful shock to a human. Is this information wrong? I know for a fact that the gfci in question did not trip for more than 2 or 3 seconds if it even tripped at all I dont remember I dropped the drill. If you dont like my posts please use the ignore button that is what it is there for. Be assured that I do not feel I am wrong as do you do not feel that you are wrong. This is why it is supposed to be a discussion and fact finding mission I do not take your posts as facts just as you do not take mine. Can you explain why the shocks were painful and long without the ground connected and why the shocks were nonexistant when the ground was connected and the gfci tripped properly or are you incapable of discussing this without becoming combative?
 
quogueelectric said:
Are entitled to your opinion. I was taught that a gfci will trip within 1/2 cycle and will trip at a threshold of .005 amps which I was also taught to be not a painful shock to a human. Is this information wrong? I know for a fact that the gfci in question did not trip for more than 2 or 3 seconds if it even tripped at all I dont remember I dropped the drill. If you dont like my posts please use the ignore button that is what it is there for. Be assured that I do not feel I am wrong as do you do not feel that you are wrong. This is why it is supposed to be a discussion and fact finding mission I do not take your posts as facts just as you do not take mine. Can you explain why the shocks were painful and long without the ground connected and why the shocks were nonexistant when the ground was connected and the gfci tripped properly or are you incapable of discussing this without becoming combative?
Click to expand...

The reason the shocks were painful and long is that you were simply a load in the circuit.

That is the reality of your test.

The fact is, the GFCI was working properly, you just didn't understand it.

As an aside, I haven't seen anybody being combative in this thread including myself, although as already noted, you need to slow down before you respond in a rude tone.

Roger
 
The load

The load

roger said:
The reason the shocks were painful and long is that you were simply a load in the circuit.

That is the reality of your test.

The fact is, the GFCI was working properly, you just didn't understand it.

As an aside, I haven't seen anybody being combative in this thread including myself, although as already noted, you need to slow down before you respond in a rude tone.

Roger
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Was to the grounded concrete not the neutral it should have tripped. I do understand it and it still did not trip
 
quogue,
GFI's do Not prevent shocks. They limit the duration. You know that.

I for one, don't know what was wrong with your older Leviton gfci (maybe this point could fit into another thread about brands?)

Maybe it was a bad one from the factory, maybe the grounded conductor was on the Load screw terminal, maybe Roger hooked it up, who knows. :)
(Sorry Roger, my old friend, I couldn't resist. Please forgive me. BTW, getting any riding in????)
But, a GFCI will work without an equipment ground being connected to it.

As far as the shocks, it is so hard to speculate without really being there, and witnessing it. I've seen some odd things, and quite frankly, nothing shocks me anymore, including shocks.
 
ty said:
quogue,
was on the Load screw terminal, maybe Roger hooked it up, who knows. :)
(Sorry Roger, my old friend, I couldn't resist. Please forgive me. BTW, getting any riding in????)
Click to expand...

I just may have hooked it up. ;)

Hello Todd, hope all is well. No I haven't been riding much, last time I pulled it out of the shed I had the rear wheel cylinder go out on me (67 FLH with drum brakes) and have been to busy to replace it, How about you? Done any Atlantic fishing lately?

Roger
 
Here's my two cents...presented as two items.

#1 I was always led to believe that the ground in your equipment existed to trip the breaker in case any exposed metal part of your equipment became energized. Since a two wire circuit has no ground, a GFI will help by shutting the circuit down if it notices that what goes out (hot) doesn't come back in (neutral)...I simplified that a little bit but if the exposed metal of your equipment becomes energized on a two wire GFI circuit, the GFI will trip if you accidentally closed the circuit between the bare metal and a ground or neutral that did NOT originate in the circuit.

#2 This is just a theory that needs disproving: Maybe instead of the bare metal becoming energized, it actually became grounded, maybe a bad neutral wire rubbing against exposed metal from inside the equipment. So instead of the imbalance occuring between the hot and neutral, you were actually just bridging a gap between neutral and another neutral or ground. I'm not clear on the mathmatics of the device. Did your equipment have three prongs plugged into the GFI?


Furthermore, I have to agree with Roger (a moderator who was put there to make decisions on how to keep this forum productive) that just because people don't agree with you doesn't mean you can act rude and nasty. If there is an ignore button ( a venture I haven't followed ) it is not there so you can be combatitive with anyone who hasn't added you to their ignore list yet, it is there to whittle the posts that a person sees down to people they trust or are merely interested in having an honest discussion with. And frankly I would be afraid of any electrician who wasn't willing to listen to another electrician's experience in the field.

I guess that was three cents. Gimme a nickel and we'll call it even.
 
quogueelectric said:
I was taught that a gfci will trip within 1/2 cycle and will trip at a threshold of .005 amps which I was also taught to be not a painful shock to a human. Is this information wrong?
Click to expand...
Yes, that is wrong. The shock will not be lethal to an average healthy adult. Pain is the eye of the beholder.

I know for a fact that the gfci in question did not trip for more than 2 or 3 seconds if it even tripped at all I dont remember I dropped the drill.
Click to expand...
Was the GFCI defective?

If you dont like my posts please use the ignore button that is what it is there for.
Click to expand...
LMAO - I think it would be a touch conterproductive for the moderators to put any member on "ignore." :D

Further, if you are wrong (as in this case), it is the responsibility of the entire membership to mention it and correct it for the education of all, not ignore it and pretend it never happened, IMO. That's one of the foundational premises of this forum, as I see it.

Can you explain why the shocks were painful and long without the ground connected and why the shocks were nonexistant when the ground was connected and the gfci tripped properly or are you incapable of discussing this without becoming combative?
Click to expand...
Without being there 15 years ago to troubleshoot it, and having to rely on your memory of events to diagnose the problem, I have no idea.
 
Quogue, I also have a strong background in electronics and theory, so we should have no problem communicating. You got a shock because of a potential difference between the tool case and the surrounding earth and/or structure.

If the continuity of the EGC prevented a shock, that's because it brought the case of the tool back to earth, where it belongs. It had a lower resistance than your body, and acted as an equipotential bond.

It is certainly within the realm of reality that, during the time that the intact EGC was preventing your shock, current was flowing on it. Why the GFCI didn't trip could be due to any of several reasons.

The presence of an EGC has no bearing whatsoever on the function of a GFCI. On the other hand, a solid connection between the supply neutral and the system ground is paramount to the GFCI functioning.

A floating (non-grounded) system cannot cause any current to flow between any one conductor and earth. (By non-grounded, I'm including absence of capacitive coupling.) If neither conductor of a circuit is grounded, contact with the other will not cause current.

Now, theory aside, it is possible that you received a shock with less than 5ma of current. It's also possible that the GFCI in question was not functioning properly. Using Ohm's law, a 24K resistance would allow 5ma to flow on 120v.

I suggest using a 22k resistor as a test load, applied between the GFCI's hot load terminal and either the circuit's EGC or an external ground. If you want a better test, use a 50K variable resistor and an AC ammeter to test the trip point.
 
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I was taught that a gfci will trip within 1/2 cycle and will trip at a threshold of .005 amps
Click to expand...
The UL standard says the maximum time to trip is equal to
T= (20/I)^1.43
where T is time in seconds and I is current in mA
That would give a maximum trip time of 7.2 seconds for a 5 mA ground fault and 2.69 seconds for a 10 mA ground fault.
Note, this is the maximum permitted time to trip and I assume that most devices would have a shorter trip time. There is no noticeable time lag when I use the test button on a GFCI and the internal resistor used results about 8mA of current at 120 volts....the trip time for an 8 mA fault is permitted to be as long as 3.7 seconds.
Don
 
larry

larry

LarryFine said:
Quogue, I also have a strong background in electronics and theory, so we should have no problem communicating. You got a shock because of a potential difference between the tool case and the surrounding earth and/or structure.

If the continuity of the EGC prevented a shock, that's because it brought the case of the tool back to earth, where it belongs. It had a lower resistance than your body, and acted as an equipotential bond.

It is certainly within the realm of reality that, during the time that the intact EGC was preventing your shock, current was flowing on it. Why the GFCI didn't trip could be due to any of several reasons.

The presence of an EGC has no bearing whatsoever on the function of a GFCI. On the other hand, a solid connection between the supply neutral and the system ground is paramount to the GFCI functioning.

A floating (non-grounded) system cannot cause any current to flow between any one conductor and earth. (By non-grounded, I'm including absence of capacitive coupling.) If neither conductor of a circuit is grounded, contact with the other will not cause current.

Now, theory aside, it is possible that you received a shock with less than 5ma of current. It's also possible that the GFCI in question was not functioning properly. Using Ohm's law, a 24K resistance would allow 5ma to flow on 120v.

I suggest using a 22k resistor as a test load, applied between the GFCI's hot load terminal and either the circuit's EGC or an external ground. If you want a better test, use a 50K variable resistor and an AC ammeter to test the trip point.
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I guess the plastic case could tell the difference from when the ground was hooked up or not . Very nice try. Btw isnt that exactly what I suggested in my 2nd post on the subject?
 
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quogueelectric said:
I guess the plastic case could tell the difference from when the ground was hooked up or not . Very nice try
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This plastic case?

quogueelectric said:
I said give me the drill and I charged up the ladder and began drilling soaking wet clothes ladder one hand on the concrete to show him it was impossible and WHAMMO I got BLASTED on my gfi receptacle where I had all the theory in the word to tell me this wouldnt happen.
Click to expand...
 
here in New York

here in New York

don_resqcapt19 said:
The UL standard says the maximum time to trip is equal to
T= (20/I)^1.43
where T is time in seconds and I is current in mA
That would give a maximum trip time of 7.2 seconds for a 5 mA ground fault and 2.69 seconds for a 10 mA ground fault.
Note, this is the maximum permitted time to trip and I assume that most devices would have a shorter trip time. There is no noticeable time lag when I use the test button on a GFCI and the internal resistor used results about 8mA of current at 120 volts....the trip time for an 8 mA fault is permitted to be as long as 3.7 seconds.
Don
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1/ 2 cycle is much faster in NY hardly enough time to feel the shock. nice try also. I will even throw you a bone with that one. The manufacturers instructions say to hook up the ground if it is there. Why bother if it is not needed?? Why worry and why did it trip almost instantaneously when hooked up? None of you have still tried this at home call mythbusters and prove me wrong if you are all so sure. I certainly do not need to try it again. Maybe the earth really is flat
 
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