GFCI

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mortimer

third party inspector
Location
New England
Occupation
retired
I know that you can replace a two wire receptacle with a GFCI receptacle if you need the grounding pin, but can you also use a GFCI circuit breaker and replace the two wire receptacle with a grounding duplex :?
 
mortimer said:
I know that you can replace a two wire receptacle with a GFCI receptacle if you need the grounding pin, but can you also use a GFCI circuit breaker and replace the two wire receptacle with a grounding duplex :?
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you can supply downstream protected receptacles, you are not supposed to connect any EGC's that are not bonded to the grounding system to said receptacles as this would bring any potential imposed by a fault in a load connected to one receptacle to anything else that particular EGC is connected to. You must also provide proper labeling "GFCI protected - no equipment ground" or something very similar to that. Many GFCI receptacles have labels included in packaging for this use. That said the labels (presuming they were utilized correctly) can be useful for any electrician coming in and trying to troubleshoot or figure things out, but are meaningless to most others.
 
mortimer said:
I know that you can replace a two wire receptacle with a GFCI receptacle if you need the grounding pin, but can you also use a GFCI circuit breaker and replace the two wire receptacle with a grounding duplex :?
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GFCI protection is not a substitute for grounding. If the appliance requires connection to an EGC you shouldn't be using it on a ungrounded circuit even with GFCI protection.
 
infinity said:
GFCI protection is not a substitute for grounding. If the appliance requires connection to an EGC you shouldn't be using it on a ungrounded circuit even with GFCI protection.
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That too, but it happens anyway, especially in old dwellings.
 
kwired said:
That too, but it happens anyway, especially in old dwellings.
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There-in lies the problem. Old home with plaster-lath walls. I can get to most of the ground floor but the plaster can't be damaged, and no wire
mold or floor receptacles.
 
IIRC, code permits <=6ft for Flex (FMC), but punts to OEM listings for suitability of grounding for armored cables without EGC
 
ActionDave said:
Maybe. It depends on how old the cable is. If it has the shorting wire in it then yes. If it is the first generation original BX then no it should not be relied on as an EGC.
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I agree that I wouldn't rely on the metal sheathing for the EGC.

Is that your opinion or is it not allowed by NEC standards.
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It is common practice to install a standard duplex receptacles with U grounds with this particular wiring method as long as there is a bonding jumper to the metal switch box.
Of course now we have to AFCI protect the receptacle or circuit if we choose to replace with the U ground receptacle.
 
Knuckle Dragger said:
I agree that I wouldn't rely on the metal sheathing for the EGC.

Is that your opinion or is it not allowed by NEC standards.
​​​​​​

It is common practice to install a standard duplex receptacles with U grounds with this particular wiring method as long as there is a bonding jumper to the metal switch box.
Of course now we have to AFCI protect the receptacle or circuit if we choose to replace with the U ground receptacle.
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NEC doesn't say anything about it. Listing standards did change at some point though.
 
mortimer said:
In old BX cable, can the shieth be used as a grounding electrode?
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Its an interesting question, updating old wiring methods and boxes for modern equipment grounding.
The 1959 NEC was the first edition that required BX to have the internal bonding strip and added a section that allowed BX (type AC) to be used for equipment grounding.
If you encounter old BX without the little internal bonding strip and your installation conforms to the code in effect at the time, you would need to consult the old code say for example the 1956 NEC.
Going by the 1956 NEC to use the cable sheath as an equipment ground you would have to use table 2595 as required by section 2611, which would require at least a 1/2 trade size cable armor.
That would be pretty big stuff probably not seen in residential, but perhaps a range or dryer.
That's just my take, I was not around back then.
But I have demo'ed lots of wiring from that time. If you have noticed how the first things required to have and equipment ground were wired ( laundry receptacles and bathrooms ) the installers of the era often ran a #14 often attached to the back of the boxes to a local water pipe in the room.
So if they had today's requirement for equipment grounding and pre 1959 BX I imagine they would have used 3 wire cable or ran a separate ECG.
 
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