GFCIs and their performance w/ and w/o EGCs

[Little Bill]

Can someone use 406.4(D) to put in a 4-prong range or dryer receptacle on a GFCI breaker?

Why would you do that when the cord on the appliance can just be changed to a 3-wire?

 

[tortuga]

Case 4 definitely stands out to me because it could potentially provide some good protection in the absence of an EGC.

Yes thats why I find 406.4(D) inconstant with its GFCI requirement, it makes no difference if the receptacle a 2-prong or a 3-prong with no EGC connected.

Case 9 is particularly interesting too because it seems as though the combination of having an EGC and not having a GFCI can lead to an even greater shock hazard (therefore adding more value to the addition of a GFCI - Case 10).

Yes And the most common case of case 9 is docks, swimming pools and spa/hot tubs with missing GFCI/RCD or no-GFCI/RCD protection.

 

[don_resqcapt19]

Yes And the most common case of case 9 is docks, swimming pools and spa/hot tubs with missing GFCI/RCD or no-GFCI/RCD protection.

In a pool or a spa/hot tube it should not be possible to touch the hot conductor. Docks are a different story because we run power out on the dock.

 

[LarryFine]

. . . I said a GFCI does NOT need an EGC to operate.

That is correct. A GFCI device does depend on the source being supplied from a grounded system to function.

In theory, a GFCI serves no purpose in a non-grounded system, as no substantial current would flow to earth.

 

[tortuga]

In a pool or a spa/hot tube it should not be possible to touch the hot conductor. Docks are a different story because we run power out on the dock.

 

[don_resqcapt19]

View attachment 2578991

I am thinking of real pools...there is nothing in the world that prevents idiots from being idiots.

 

[wwhitney]

In theory, a GFCI serves no purpose in a non-grounded system, as no substantial current would flow to earth.

Well, it would still serve to trip if one of the downstream circuit conductors had a high impedance inadvertent connection to a line conductor that is upstream of the GFCI. Not very likely.

Cheers, Wayne

 

[tortuga]

Well, it would still serve to trip if one of the downstream circuit conductors had a high impedance inadvertent connection to a line conductor that is upstream of the GFCI. Not very likely.

Cheers, Wayne

Thats what PV system GFCI's do right?

 

[MechEdetour]

That is correct. A GFCI device does depend on the source being supplied from a grounded system to function.

In theory, a GFCI serves no purpose in a non-grounded system, as no substantial current would flow to earth.

I actually made a thread on this very topic back in 2018 - I can't believe it's been 7 years since.

GFCI on ungrounded system (system grounding, not equipment grounding)

A GFCI receptacle will work on a 2 wire circuit (grounded system) without an equipment ground. It senses current imbalances between the hot and neutral, which when present, it will trip. This makes sense to me and there is no less than a thousand articles on this topic. However, my questions is...

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