GFCI open line and neutral conductors?

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Can someone tell me if GFCI receptacles designed for permanent installation are required by NEMA, UL, or some other body to open both the line and the neutral conductors?

Thanks!
 

Little Bill

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Tennessee NEC:2017
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Can someone tell me if GFCI receptacles designed for permanent installation are required by NEMA, UL, or some other body to open both the line and the neutral conductors?

Thanks!

Can't speak for older ones, but all the current GFCIs open both conductors.
 

kwired

Electron manager
Location
NE Nebraska
Can someone tell me if GFCI receptacles designed for permanent installation are required by NEMA, UL, or some other body to open both the line and the neutral conductors?

Thanks!

By design they would not work if they did not protect both lines. They have a current transformer in which all conductors of the circuit pass through. As long as all current that goes out to load(s) on any conductor returns on other conductors passing through the CT, the CT sees a net of zero and has no output voltage to run the trip circuitry.
 
By design they would not work if they did not protect both lines. They have a current transformer in which all conductors of the circuit pass through. As long as all current that goes out to load(s) on any conductor returns on other conductors passing through the CT, the CT sees a net of zero and has no output voltage to run the trip circuitry.


Thank you, kwired, but the question is when the ground fault CT reaches its threshold and trips, will it open the line and the neutral pathways or just the line? And is this required by UL or NEMA?

Thanks!
 

kwired

Electron manager
Location
NE Nebraska
Thank you, kwired, but the question is when the ground fault CT reaches its threshold and trips, will it open the line and the neutral pathways or just the line? And is this required by UL or NEMA?

Thanks!
I don't know what UL standards are, but all I have ever seen interrupts all protected lines, and I am guessing that is a standard also.

If you think about it, a GFCI can trip if an outside voltage and current is somehow imposed on a protected circuit. Though it wouldn't remove the source in this instance if it opens, it still makes some sense to interrupt all protected lines.
 
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