Basement GFCI's or NOT ?

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infinity said:
They should have provided a definition of the word basement. :)
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That rings an old distant bell somewhere in the catacombs of my memory. . . . back when GFCI protection was first introduced for the unfinished areas of basements 40 odd years ago, didn't the NEC have a similar discussion? Wasn't there something about how much of the wall is below grade?

Edit to add: Originally the problem was understood that the concrete floor of a basement was a good conductor and that a person in bare or stocking feet would be "connected" electrically. Upon touching an energized surface, the person would be shocked. Hence the GFCI for "personnel safety". It was judged, at that time, 40 odd years ago, that the "finishing" of a space reduced the quality of the electrical connection to the slab on grade because of the floor finishing.

Now, in 2020, the personnel protection is being extended to when the normally dry "finish" is no longer dry.
 
al hildenbrand said:
That rings an old distant bell somewhere in the catacombs of my memory. . . . back when GFCI protection was first introduced for the unfinished areas of basements 40 odd years ago, didn't the NEC have a similar discussion? Wasn't there something about how much of the wall is below grade?

Edit to add: Originally the problem was understood that the concrete floor of a basement was a good conductor and that a person in bare or stocking feet would be "connected" electrically. Upon touching an energized surface, the person would be shocked. Hence the GFCI for "personnel safety". It was judged, at that time, 40 odd years ago, that the "finishing" of a space reduced the quality of the electrical connection to the slab on grade because of the floor finishing.

Now, in 2020, the personnel protection is being extended to when the normally dry "finish" is no longer dry.
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"the concrete floor of a basement was a good conductor" Found that out the hard way years ago kneeling on a concrete floor installing outlets live.?
 
ActionDave said:
I would be all in favor of a 100% GFPE level of protection. It would be a huge improvement over what we have now and we would all be much safer. I know that it would not provide the same life safety protection as GFCI but it would sniff out almost all ground faults before they became a life safety issue and there would not be the issue of false trips that can happen with GFCI level protection.
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that would make sense
:thumbsup:
~RJ~
 
al hildenbrand said:
That rings an old distant bell somewhere in the catacombs of my memory. . . . back when GFCI protection was first introduced for the unfinished areas of basements 40 odd years ago, didn't the NEC have a similar discussion? Wasn't there something about how much of the wall is below grade?

Edit to add: Originally the problem was understood that the concrete floor of a basement was a good conductor and that a person in bare or stocking feet would be "connected" electrically. Upon touching an energized surface, the person would be shocked. Hence the GFCI for "personnel safety". It was judged, at that time, 40 odd years ago, that the "finishing" of a space reduced the quality of the electrical connection to the slab on grade because of the floor finishing.

Now, in 2020, the personnel protection is being extended to when the normally dry "finish" is no longer dry.
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40 years ago the changes to NEC used to make sense, now they are just looking for things because they think they have to make changes it seems.

I have no issue with the reasoning when GFCI's were first expanded in many areas back then, they all were mostly about having grounded surfaces around and they all applied to 15 and 20 amp 120 volt receptacle applications where it is pretty common to see compromised EGC pins on the cord connectors, which puts users of that equipment at a high risk if there is a fault in the equipment. In more recent years it has been lets add this or that with no real justification to how much of a risk really exists. You know darn well it is manufacturer's submitting the PI's and pressuring the CMP's with "what if" scenarios and it has gotten to the point of no common sense.

4-6 mA of leakage is just too low to apply to everything without having nuisance trips, and then that becomes the electricians problem when at very least GFPE level protection makes much more sense in most applications where losing an EGC isn't all that likely.

Now we have changed the basement thing - why? And if basements are so dangerous why just change the dwelling basements? And why is a house on a slab any more or less dangerous?

It is stupid.
 
kwired said:
40 years ago the changes to NEC used to make sense, now they are just looking for things because they think they have to make changes it seems.
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This rings true to me. It seems that additional levels of protection are being required 'because we can'.

This is not to say that we shouldn't improve safety; remember that the intent of the code is 'practical safeguarding' not 'perfect'. And 'practical' needs to consider cost/benefit analysis.

It seems to me that for some things we should have a 'roadmap' that says 'this additional protection will be required in the future if the price falls below X' eg additional locations for GFCI protection. Because some areas are _slightly_ safer with GFCI but the benefit doesn't currently outweigh the cost.

-Jon
 
winnie said:
This rings true to me. It seems that additional levels of protection are being required 'because we can'.

This is not to say that we shouldn't improve safety; remember that the intent of the code is 'practical safeguarding' not 'perfect'. And 'practical' needs to consider cost/benefit analysis.

It seems to me that for some things we should have a 'roadmap' that says 'this additional protection will be required in the future if the price falls below X' eg additional locations for GFCI protection. Because some areas are _slightly_ safer with GFCI but the benefit doesn't currently outweigh the cost.

-Jon
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This basement GFCI thing doesn't bother me too much when it comes to what it adds to getting the job done, it will mostly mean using a dual function AFCI/GFCI breaker instead of a CAFCI, it is just the reasoning why they made the change (which I have not researched yet) that bugs me on this particular change. Seems they are addressing a mostly non existing problem, and if anything some consistency would at least have included non dwellings also.

What does bug me is the change in 2017 that added many more places where other than 15/20 amp 120 volt applications were added to the GFCI protection requirements, and the only justification I could find for it was something to the effect of 'we have the ability to do this now'. Sounds like how AFCI's got introduced and expanded to me, no real evidence of the need or that it will do what they say it will do.

And guess what, the AFCI manufacturers also make GFCI's.
 
kwired said:
I would be more willing to accept that reason if they had changed 210.8(B)(10) in a similar manner.

House on a slab is also prone to flooding more than one with floors above grade, but then a house in low lying area might be more prone to flooding on any floor than some basements are. I think they are pushing too far with this one no mater what the reason might be, and you know the device makers probably pushed for it.
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Device makers pushing for anything is about monetization which has to stop. One time I responded to a flooded equipment pit in a ranch-industrial setting. The sump pump was on a 115V GFCI outlet , which tripped and flooded a much more expensive piece of equipment. Attempting to Engineer around proper education and common sense will always fail. Any sump pump system that is not FAILSAFE and does not also have redundancy is asking for a flood. This thing is being approached backwards and for the wrong reasons, unless I am missing something.....
 
StarCat said:
Device makers pushing for anything is about monetization which has to stop. One time I responded to a flooded equipment pit in a ranch-industrial setting. The sump pump was on a 115V GFCI outlet , which tripped and flooded a much more expensive piece of equipment. Attempting to Engineer around proper education and common sense will always fail. Any sump pump system that is not FAILSAFE and does not also have redundancy is asking for a flood. This thing is being approached backwards and for the wrong reasons, unless I am missing something.....
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You are not missing anyting. Sump pump is one application that at very least should have GFPE instead of GFCI. So far it is still allowed on snow/ice melting equipment and for good reason, normal leakage may very well exceed GFCI threshold.

Some complain about GFCI in unfinished basements, garages, etc. and the loss of power to a refrigerator or freezer and loss of contents - that one I do agree with the code as I have seen too many refrigerators or freezers with a missing EGC pin in the cord (or even really old ones that never had a EGC in the cord) that developed a ground fault and were shocking people when they touched it.
 
Something that I've suggested in the past is a ground fault detecting receptacle that provides GFPE levels of protection if the fault current returns on the ground pin, but GFCI protection otherwise. This would permit a metal chassis device to function with larger leakage from circuit to chassis to ground pin, but still trip if the fault went 'outside' of the frame.

It wouldn't provide protection for a person touching the frame and the circuit, but again this is a practical safeguarding thing. With a fridge the wiring is contained and the shock hazard is if a fault energizes the frame.

-Jon
 
winnie said:
Something that I've suggested in the past is a ground fault detecting receptacle that provides GFPE levels of protection if the fault current returns on the ground pin, but GFCI protection otherwise. This would permit a metal chassis device to function with larger leakage from circuit to chassis to ground pin, but still trip if the fault went 'outside' of the frame.

It wouldn't provide protection for a person touching the frame and the circuit, but again this is a practical safeguarding thing. With a fridge the wiring is contained and the shock hazard is if a fault energizes the frame.

-Jon
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How do you propose to make that work? The simple method won't work because in order for it to leak 20 mA to the EGC pin you will already be exceeding the 4-6 mA threshold of the GFCI function and it should trip anyway. How is the device to know where it is going once it leaves the hot/neutral slots of the receptacle, and even if monitoring the EGC and it is over 6 mA but less than 30, 100 or whatever, that current could be coming from someplace else besides the GFCI protected hot and neutral.



Even with currently used GFCI protection devices, if you touch that energized appliance frame you will still get shocked during the time it takes for the GFCI to respond, but the GFCI is detecting the fault and opening the circuit instead of allowing the shock to continue. And ~5 mA will wake you up if you encounter it. Want to test that theory, plug a GFCI tester into a weatherproof metal covered receptacle that has no EGC and press the test button while contacting the metal cover. If that doesn't happen to work stand barefooted on wet ground and try it again. It will put at least ~5 mA of test current through you unless your resistance to ground is too high.
 
I believe Franklin pump suggested using GF CT detection around all conductors to the pump, including the EQ. The EG would return most of the fault current as normal but if the leakage became excessive via dart, it would trip. IDK if that suggestion is still in their manual.
 
The basements in all the houses I've lived in have been what I consider "damp." Unsealed concrete block on unsealed concrete floor with no vapor barrier and no external seal on the block walls. Sealing and vapor barriers weren't considered back in 1953!

My current house has seepage in heavy rains. Other than that, the floors and walls are what I consider 'dry but damp.' The outlets for my power tools have consumer-grade GFCIs. The table and chop saws have not triggered the GFCI (so far).

I consider the GFCIs reasonable insurance against problems with electricity!

Now, the single outlet in the garage is not a GFCI....
 
wwhitney said:
The manufacturer would use one CT around hot, neutral, and EGC and trip the device at the usual 4-6 ma. Then there would be another CT around hot and neutral only, with a 30 ma trip level.

Cheers, Wayne
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Wouldn't that not trip if the fault is returning entirely on the EGC and is below 30 mA? Only way the 4-6 mA component works is if fault current returns outside the three conductors being monitored. Probably sort of works but if in situation where EGC is the only path for fault current to take you still get shocked without tripping the device.

You also sort of have to make it an isolated ground type receptacle or you will get parallel EGC paths anyway and could even introduce trip conditions from stray current from other circuits.
 
kwired said:
Wouldn't that not trip if the fault is returning entirely on the EGC and is below 30 mA?
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Yes, that is what winnie proposed. GFPE level trips where the fault is returning entirely on the EGC, and GFCI level trips otherwise. I have no opinion on the merits, I was just answering your question.

kwired said:
You also sort of have to make it an isolated ground type receptacle or you will get parallel EGC paths anyway and could even introduce trip conditions from stray current from other circuits.
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I don't think that would be a problem, you'd just isolate the ground pin wiper from the other parts of the receptacle connected to the EGC, and then use an insulated conductor to connect them back together, passing the insulated conductor through the GFPE level CT.

Cheers, Wayne
 
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