Why GFCIs were mandated- a personal perspective

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iwire said:
Lets start here



Th above tells us we have to comply with both A & B, not one or the other.




The above lays out what activities this applies to and what sections we have to comply with



That is the very limited exception to the GFCI protection required by section (A).




(A)(1) above applies unless you fit the narrow limitations of the exception above. No assured grounding program allowed for those receptacles.

Now lets move on to (B) where we can find the assured grounding program.



So section (B) does not apply to any 125 volt, 15, 20 and 30 amp receptacles and therefore the assured equipment grounding program cannot be used for those receptacles.

Assured equipment grounding can only be used in place of GFCI for circuits greater than 30 amps and 125 volts.
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Which boils down to this:

The code openly lets you skip GFCI protection on 125 volt circuits 30amps under for industrial locations with qualified personnel. To me it sounds like code would rather have GFCI protection everywhere, but somehow makes a special allowance if they know the EGC will remain intact.

Does OSHA not have something similar for job sites?


Second circuits over 125 volts can skip the GFCI. I know you say that might be because GFCI protection is not easily available for 250 volt circuit, but I disagree. If code requires it eventually manufactures will make it, I doubt code would leave that option out for so long is GFCI were really needed.
 
al hildenbrand said:
Sure. That is an instance. But it is not the continuum of what "current leakage from the insulated circuit path" covers. What about all manner of mis-wiring?
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Miswiring? Of course. Do you know how many pool pumps have been miswired by not having an EGC only to become electrified? Hence why pool pumps outside of locations likely to see unqualified personnel require a GFCI.




What about an open neutral with the live conductor short to EGC connected exposed metal in the hands of a person working on the end of a long small guage branch circuit and extension cord, a person who is exposed to an intimate connection with Earth?
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Open neutral where? At the service? If so a GFCI will not protect you.






image449.png

In this scenario, the GFCI detection is absent, but there is a good EGC. Circuit analysis yields a whooping 56 mA through body "leak".

image440.png
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I agree in such a scenario the GFCI would certainly speed up clearing a fault since the EGC impedance will limit fault current and thus the breaker would take longer to open. But if the above scenario was such a concern, why does the NEC only make recommendations- not mandatory restrictions- on voltage drop?


And I know that posters from here on in will quip " the NEC does not cover a extension cords so voltage drop would not matter anyway"

Correct. Until someone runs a 400 foot run of 10-3 THHN/THWN in conduit to a remote structure. I can legally have 25% or more voltage drop and a breaker that takes several seconds to clear a short circuit replicating the above scenario all while under the NEC.
 
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Just to address this because I missed it :ashamed1:

al hildenbrand said:
I find this conclusion to be a disturbing misdirection.

Load current is intended to stay in an insulated,
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Then why does the code let you get away with an un-insulated service neutral? I know I am nit picking, but technically this statement is not correct.


and contained, path, from the source, through the load and back to the source. Detection of leakage of current, and the interruption of the leakage current, from that intended path is the purpose of the GFCI. Period.
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Correct. However that fact does not change history.
 
I'm hearing the '17 will require GFCI protection for all commercial receptacle outlets 100A and less....

Inasmuch as GFCI protective devices exist for say 100A 3ph, i don't believe there is a 100A 3phgfci breaker on the market....at least not yet


~RJ~
 
romex jockey said:
I'm hearing the '17 will require GFCI protection for all commercial receptacle outlets 100A and less....

Inasmuch as GFCI protective devices exist for say 100A 3ph, i don't believe there is a 100A 3phgfci breaker on the market....at least not yet


~RJ~
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One must ask... what were the substantiations?
 
I'd wager it mortality & morbidity MBrooke , it always is

The irony is trying to address all the 3rd world junk we power up...

~RJ~
 
mbrooke said:
Then why does the code let you get away with an un-insulated service neutral? I know I am nit picking, but technically this statement is not correct.
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You're kidding, right?

The load side of a class A GFCI is not in the Service Conductors.

mbrooke said:
Correct. However that fact does not change history.
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Again this is a baseless misdirection, in my opinion.

The "Fact," as I stated it, and as you agreed is "Correct," IS HISTORY. Your own reference to source material about 1962 in this thread says so.

mbrooke said:
Open neutral where? At the service? If so a GFCI will not protect you.
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The open neutral can be anywhere in the branch circuit, extension cords or tool.

mbrooke said:
But if the above scenario was such a concern, why does the NEC only make recommendations- not mandatory restrictions- on voltage drop?
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That is a total misdirection, as voltage drop does not preclude the presence of current escaping the intended circuit path.

Your OP reductionist claim:
mbrooke said:
GFCIs, they were simply- and still are- another type of EGC. They were created and mandated soley to address the issues asociated with missing EGCs. Not water or moisture.
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is countered by my illustrated scenario, as there is an intact EGC present, and the quality of the poor worker's connection to Earth is augmented by water and/or moisture.

I chose to illustrate a construction power setting, purely for the engineering analysis simplification of the resulting equivalent circuit. . .Historically, exterior dwelling GFCIs were mandated very early in the roll out, over the decades, of GFCI requirements.
 
You kind of get used to the current wiring techniques that are used today until you a faced with dealling with older ones.
Yes, those aluminum housed electric tools with 2-wire cords were scary. Get a shock? No problen, simply just reverse the plug ;)

My son's next door neighbor asked for my opinion on changing outlets that he had in his great room to grounding outlets for his electronic equipment. He had a home run circuit consisting of 12/3 NM with 20at breakers and no EGC. Each outlet around the room were split between the lines. What was even more interesting was that about in the middle of the run was a large 240v through the wall mounted A/C powered by the L-L conductors with a 240v receptacle.
Wanting to replace them with grounded receptacles was a problem as today's electronics are best grounded for stability. Yes, GFCIs could be used with no EGC and marked as having no EGC which are allowed but that would not solve the issue and the need for an EGC.
Replacing the circuit would have been an ideal solution except the issue was componded by the structure being built on a slab, no basement.
This house I believe was built is a small community back around 1960 where inspections were slim to none at best. Without researching the code from back in that time I'm not to sure that it even met code.
 
They were mandated because practical cost effective technology became available to reduce the incidence of shock
it has worked
 
al hildenbrand said:
You're kidding, right?

The load side of a class A GFCI is not in the Service Conductors.
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Correct, they are not.


Again this is a baseless misdirection, in my opinion.

The "Fact," as I stated it, and as you agreed is "Correct," IS HISTORY. Your own reference to source material about 1962 in this thread says so.
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That is the authors interpretation. My reason for posting it is the old NEC articles which in themselves support my claim IMO.

The open neutral can be anywhere in the branch circuit, extension cords or tool.
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Correct, and that would not energize the shell of a metal drill or effect the fault current path on an EGC.


That is a total misdirection, as voltage drop does not preclude the presence of current escaping the intended circuit path.
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It certainly does not nor have I denied it, but the increased EGC impedance results in a longer breaker operating time and in turn the user is exposed to more voltage for a longer period of time relitive to remote earth which I assumed is what you were trying to communicate in your graphic. If so, yes a GFCI would trip faster than a breaker.



Your OP reductionist claim:

is countered by my illustrated scenario, as there is an intact EGC present, and the quality of the poor worker's connection to Earth is augmented by water and/or moisture.
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Yes- water lowers the resistance of the person. As does other factors like a concrete floor.


However, in most cases the run is not long enough to result in an OCPD clearing time being long enough to result in injury to the user. Conservative international standards in this same scenario allow a 0.8 second OCPD clearing time- and while I could be wrong I doubt the CMP had that in mind when mandating GFCIs.

I chose to illustrate a construction power setting, purely for the engineering analysis simplification of the resulting equivalent circuit. . .Historically, exterior dwelling GFCIs were mandated very early in the roll out, over the decades, of GFCI requirements.
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And I am not surprised. 2 prong tools in an environment where a person is likely to have a lowered impedance makes for a deadly scenario.


This is not to say your graphic is incorrect. However I doubt that is the exact scenario the CMPs had in mind especially when there was no EGC on many power tools to begin with.
 
Excellent thread... :)

I am new to this forum... was browsing around and read this thread...
Now I understand why this forum was recommended.

THX to Mike and the moderators for the forum...
I can see this will be an asset to my small business in the future.

For now:
Merry Christmas,
Happy New Year,
Happy Holidays,
And an equal positive holiday wish to any other faith or belief I did not cover.

GA
 
GA-HVAC-Tech said:
Excellent thread... :)

I am new to this forum... was browsing around and read this thread...
Now I understand why this forum was recommended.

THX to Mike and the moderators for the forum...
I can see this will be an asset to my small business in the future.

For now:
Merry Christmas,
Happy New Year,
Happy Holidays,
And an equal positive holiday wish to any other faith or belief I did not cover.

GA
Click to expand...

Thank you for posting :)


I hope you stay and share your own knowledge as well in the process.



Happy Holidays as well :)
 
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