GFCI protection DANGEROUSLY misunderstood. Change my mind

[darkenergy]

For whatever reason, I have had this discussion quite a few times in the last six months or so with various people.

it would appear based on these discussions with various types of people, A HUGE PERCENTAGE BELIVE that a GFCI receptacle protects the individual from any electrical shock/electrocution hazard. My explanation…

'If you become Mr./Mrs./Ms./other… Resistor (Load), between the hot/ungrounded conductor/black wire/little slot on the plug/receptacle, and the neutral/grounded conductor/white wire/big slot on the plug/receptacle, you will just fry and dance until (A) someone turns of the power source (B) the cows come home… On the condition that there is no other 'leakage current' to a grounded surface of any kind.'

My question is:
(1) is there a better way to explain this, ESPECIALLY to the average person?
(2) am I just getting older/fatter/crazier/wrong?

All comments and critiques are welcome and would be appreciated.

Thank you, Willy

P. S. I did search the site to the best of my ability but could find no corroboration/posts

 

[infinity]

'If you become Mr./Mrs./Ms./other… Resistor (Load), between the hot/ungrounded conductor/black wire/little slot on the plug/receptacle, and the neutral/grounded conductor/white wire/big slot on the plug/receptacle, you will just fry and dance until (A) someone turns of the power source (B) the cows come home… On the condition that there is no other 'leakage current' to a grounded surface of any kind

I agree, but I think that the reason it's called a ground fault circuit interrupter is because the majority of shocks/electrocutions come from a grounded object not the neutral.

 

[augie47]

Mike has a graphic of how they work which shows the current flow to earth. I have not found one that explains GFCI does not protect phase to neutral shocks but the graphic might help in your explanation.

 

[winnie]

My verdict: true but misleading.

It is absolutely true that a GFCI will not protect from a pure H-N shock. Anyone who claims that GFCIs will prevent all shocks is blowing smoke.

GFCIs are tremendously effective at preventing most shocks because most shocks involve some sort of H-G current flow.

I don't think there is any way to explain this to someone who doesn't understand what a circuit is. You can try using the term 'balance' in the qualitative sense even though for GFCIs it actually applies in the quantitative sense.

"A GFCI does not detect shocks. It detects current imbalance. Most shocks create current imbalance and the GFCI trips. But if you get yourself into the circuit in a perfectly balanced way, the current will remain balanced, you will get shocked, and the GFCI won't trip."

-Jon

 

[Bill1974]

You are correct. If the individual having the magic pixies pumped though them is not leaking any of those pixies to somewhere else they will continued to get pixies pumped through them. The reality is that in most cases the individual is not perfectly insulated and does leak some of the pixies somewhere other than the neutral. Also from a safety standard it requires you to be part of the current path, a double fault condition, you have to touch the hot and neutral. In most cases contact is made to the hot or neutral, if they have no path to flow current to, all is fine. If they happen to be grounded or touching something that current can flow to the GFCI should trip once these is sufficient current imbalance.

 

[Chamuit]

I tell folks to imagine a loop. Power comes in one side and out on the other. That flow is balanced. When it isn't (I don't go into measurements), the GFI senses that and trips. If they ask an informed question, I go on from there.

 

[don_resqcapt19]

...
GFCIs are tremendously effective at preventing most shocks because most shocks involve some sort of H-G current flow.
...
-Jon

They don't really prevent the shock...they just limit the duration of the shock. The shock has to occur with enough current flow for the GFCI to sense and react too.

 

[xformer]

Just plug a light into the GFCI and turn the lamp on. That should explain everything one needs to know about the GFCI function between Hot and Neutral.

 

[winnie]

They don't really prevent the shock...they just limit the duration of the shock. The shock has to occur with enough current flow for the GFCI to sense and react too.

Quite correct, let me rephrase:

GFCIs are tremendously effective at reducing the severity of most shocks because most shocks involve some sort of H-G current flow.

 

[Strathead]

People are also under the assumption that circuit breakers protect people too. I just don't see it as an issue to lose sleep over, as Winnie said, they protect from most shocks a layman would potentially come in contact with. Chock the rest up to Darwin.

 

[drcampbell]

Circuit breakers do protect people from a hot-to-metal-case fault if there's a continuous equipment-grounding conductor.
Some hot-to-human-to-earth electrocutions were prevented before GFCIs were deployed.
(though I do wonder why a toaster with a metal case, exposed elements and a 2-wire cord is permissible)

 

[darkenergy]

Thank you all for taking the time and effort to reply.
My apologies for the word salad.

I should have qualified my statement. I did explain to the best of my ability, and I would agree wholeheartedly that GFCI's are a great thing. I did state what GFCI meant, but could not communicate that effectively. Many, many people disagreed vociferously with me.

It was not until I read the post by xformer that the light went on in my head. Thank you for that.

The thought never occurred to me, (apprentice rocket scientist) to use the lamp analogy. I suppose any electrically operated device would serve the same purpose, But I didn't think of that either. (See: apprentice rocket scientist)
The lamp idea was very illuminating, even I could grasp the concept.

Too caught up in the minutia to step back and think about it logically, thanks again!

I don't think anybody could misunderstand that ( lamp/light bulb)

Sincerely, Can't see the forest for the trees.