GFCI on 2-wire circuit

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#1

Originally Posted By: roconnor
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The subject of a 3-prong GFCI kitchen receptacle on a 2-wire circuit came up in a QOD, so I thought posting it here might be interesting. The question was, if that receptacle was not marked “No Equipment Ground” as required by model codes is that then a “Safety Hazard”.


To me, a Safety Hazard is something that is an immediate danger, which requires correction by a licensed professional right away. I think it would be something to note, and maybe even a "Safety Concern" ... but not a "Safety Hazard". A ground wire is not needed for a GFCI to operate correctly, which is why the NEC allows an old 2-prong receptacle to be replaced with a 3-prong GFCI receptacle.

The down side is if there is a ground fault somewhere, the breaker would not trip to clear the fault ... as there is no connection back to the neutral at the service panel. This could damage equipment intended to be grounded, but there should still be "people protection" provided by the GFCI device.

Lets say ya plug a drill with a 3-prong cord into that outlet, and the drill has a short of a hot wire to the metal case (casing fault). The fault would not be cleared by the breaker. But if someone came along and touched the hot drill case and say a metal faucet, the GFCI should detect the hot-neutral imbalance and trip. Yes, you would get a shock, but you shouldn't get badly hurt or killed if the GFCI operates properly.

So I'm just not seeing a "Safety Hazard" there ... but fire away ... ![icon_wink.gif](upload://ssT9V5t45yjlgXqiFRXL04eXtqw.gif)

--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong

#2

Originally Posted By: Mike Parks
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Robert


I say yes it is a safety hazard. Why?

90-1.(a) 1996 (the one I keep by the computer for quick reference).

Practical Safeguarding.

Mike P.

#3

Originally Posted By: Bob Badger
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Robert when we were talking about this here http://www.nachi.org/bbsystem/viewtopic.php?t=3504 you said:


roconnor wrote:
Sound's like you have lost some faith in GFCI's Bob. Send me an email, or maybe start a topic, so we can knick it around some more without dragging out the QOD.


The answer to that is no not at all, I think GFCIs are one of the most significant piece's of electrical safety equipment to come along. ![icon_cool.gif](upload://oPnLkqdJc33Dyf2uA3TQwRkfhwd.gif)

That said I would rather protect people from getting exposed to an electrical shock in the first place.

I am not comfortable with saying "Oh well it is GFCI protected, no further protection is necessary"

I do agree with you that the addition of the sticker will change little, but from my point of view on old two wire systems I would prefer to see a GFCI breaker and a two wire replacement outlet used. (This is an opinion, not code )

JMO, Bob

FWIW here is a 3000 amp GFCI (OK GFP ) breaker I installed and a 'doorbell' transformer

The breaker is at the extreme left of frame.

![](upload://nMgoT2JHxh0bA8ajWXVnfIY3X3D.jpeg)

--
Bob (AKA iwire)
ECN Discussion Forums
Mike Holt Code Forum
#4

Originally Posted By: gbeaumont
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Hi Bob, that “doorbell” must make your ears bleed when it goes off!!


Gerry

--
Gerry Beaumont
NACHI Education Committee
e-mail : education@nachi.org
NACHI phone 484-429-5466

Inspection Depot Education
gbeaumont@inspectiondepot.com

"Education is a journey, not a destination"

#5

Originally Posted By: Dave Nix
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Bob,


Nice install ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)

One question, do you always shine your conduits to be sure you comply with 110.12??



--
Dave Nix
Electrical Matters

#6

Originally Posted By: roconnor
This post was automatically imported from our archived forum.


Mike Parks wrote:
I say yes it is a safety hazard. Why? ... 90-1.(a) 1996 ...

Is NEC 406.3(D)(3) which permits that receptacle to be installed a mistake? I don?t think so.

Bob Badger wrote:
... I would rather protect people from getting exposed to an electrical shock in the first place. ... on old two wire systems I would prefer to see a GFCI breaker and a two wire replacement outlet used.

I agree, but I think that 3-prong cheater plug will come out so fast it would make your head spin. Then you are back to square one.

I think the NEC allows a 3-prong GFCI on a 2-wire system because there would be ?people protection? ? just no ?equipment protection?, which I think is the reason for the sticker.

To me not having equipment protection is a concern, but not a safety hazard ... just my 2-nickles

--
Robert O'Connor, PE
Eagle Engineering ?
Eagle Eye Inspections ?
NACHI Education Committee

I am absolutely amazed sometimes by how much thought goes into doing things wrong
#7

Originally Posted By: Mike Parks
This post was automatically imported from our archived forum.


Robert


I was responding to "The question was, if that receptacle was not marked "No Equipment Ground" as required by model codes is that then a "Safety Hazard". "

Not to a GFCI being installed.

Mike P>

#8

Originally Posted By: Blaine Wiley
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I would not define it as “safety hazard” or “safety concern”. I would write up a “safety issue” describing the condition and that a sticker indicating no equipment ground was not present.

#9

Originally Posted By: Mike Parks
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I like Blaine’s post.


Mike P.

#10

Originally Posted By: tallen
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How many (average)Home Owners are going to know what equipment ground means icon_question.gif And how many home owners will remove an ugly sticker for aesthetic reasons icon_question.gif

–
I have put the past behind me,


where , however, it now sits, making rude remarks.


www.whiteglovehomeinspections.net

30 Oct 2003-- 29 Nov2005
#11

Originally Posted By: roconnor
This post was automatically imported from our archived forum.


Blaine … I think we are on the same page. To me a “safety concern” and “safety issue” are the same thing … maybe even just a “concern”. It is something to point out, but there is no apparent immediate danger that would require evaluation/correction by a licensed professional right away … icon_wink.gif

–
Robert O’Connor, PE


Eagle Engineering ?


Eagle Eye Inspections ?


NACHI Education Committee


I am absolutely amazed sometimes by how much thought goes into doing things wrong
#12

Originally Posted By: Blaine Wiley
This post was automatically imported from our archived forum.


Would a “Safety Hazard” not fall into the category of a “Material Defect” because it represents an unreasonable risk to someone on the property?

#13

Originally Posted By: Bob Badger
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This first item shows what the different current levels can do to a human.




This next text come right out of the 2002 NEC Handbook.


Quote:
GFCIs operate on currents of 5 mA. Listing standards permit a differential of 4 to 6 mA. At trip levels of 5 mA (the instantaneous current could be much higher), a shock can be felt during the time of the fault. The shock can lead to involuntary reactions that may cause secondary accidents such as falls. GFCIs will not protect persons from shock hazards where contact is between phase and neutral or between phase-to-phase conductors.


I do not believe that the NEC intends the GFCI to take the place of a grounding conductor at replacement receptacles, that is the reason for the marking requirement.

If the NEC intended the GFCI to take the place of a grounding conductor changes would have to be made to 250.114.

--
Bob (AKA iwire)
ECN Discussion Forums
Mike Holt Code Forum