I recently installed some QO 1pole GFCI circuit breakers on 2 wire (no EGC) branch circuits. The devices are existing 3 prong duplex receptacles without an EGC connected. When I attempted to trip the breaker using a conventional 3(eye) testing device I couldn't get the breaker to trip.I contacted Square D T/A and they told me that as long as the trip device on the breaker works it is funtioning properly. The local inspector tells me that the breaker has to trip using the GFCI testing device at the receptacle. Anybody here ever run into a similiar situation?
2 wire circuit/GFCI breaker
- Thread starter nizak
- Start date
- Status
- Location
- Massachusetts
The inspector is wrong, Square D is correct.
It is imposable for a plug in tester to trip a GFCI on a two wire circuit, it has no place to 'leak' current to.
The inspector needs to become more knowledgeable.
It is imposable for a plug in tester to trip a GFCI on a two wire circuit, it has no place to 'leak' current to.
The inspector needs to become more knowledgeable.
- Location
- Logan, Utah
None, a GFCI device does not require an EGC to function.
But, the cheap GFCI receptacle testers with the little button on them use the EGC to create the imbalance used to trip the GFCI device.
The only recognized test for proper function of a GFCI device is the test button on the device itself.
Chris
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
To be precise, the portable GFCI testers try to send a small "leakage current" from the hot conductor to the EGC. That will allow the internal electronics of the GFCI device to sense a difference in current between the hot conductor and the neutral, which in turn causes the GFCI to trip. But if there is no EGC available, then there is no way for the portable GFCI tester to create this “leakage current.” That is why the portable testers cannot work, even if the GFCI device itself is perfectly functional.
By contrast, when you push the test button, the GFCI device's internal electronics will send a small "leakage current" from the hot to the neutral. That current path is available, even if there is no EGC. That is why the test button will succeed in verifying the GFCI device's operation, even without an EGC.
By contrast, when you push the test button, the GFCI device's internal electronics will send a small "leakage current" from the hot to the neutral. That current path is available, even if there is no EGC. That is why the test button will succeed in verifying the GFCI device's operation, even without an EGC.
Last edited:
- Location
- New Jersey
- Occupation
- Journeyman Electrician
What kind of inspector told you this?
- Location
- Logan, Utah
stevebea
Senior Member
- Location
- Southeastern PA
A very uninformed kind.:grin:
Chris
There's alot more inspectors just like that out there. The last time I had this very same situation I explained to the inspector why his GFCI tester would not work on a 2-wire circuit he looked at me like he thought my logic was believable but said he would have to make a few phone calls. He called me back three days later saying he would accept using the test button to verify proper gfi operation.
Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
You need to educate the inspector. You need to do it gracefully. What you can do demonstrate the ground fault with a cord a load and using the gounded metal of the service to show the breaker will trip. There is no way that a standard plug tester will demostrate proper operation nor is it required to do so. If you are using the GFCI breaker becuase you have ungrounded branch circuit you are doing what is correct. Otherwise the inspector is correct.
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