Scott Shaw
Member
- Location
- Texas
- Occupation
- HVAC & Electrical Contractor
Will A GFCI receptacle trip correctly without a Equipment grounding conductor. I used Code article 406-d2 (c) and the GFCI will not trip? I must be doing something wrong?
Equipment Ground on a GFCI
- Thread starter Scott Shaw
- Start date
- Status
synchro
Senior Member
- Location
- Chicago, IL
- Occupation
- EE
How are you trying to make it trip?
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
As synchro is alluding to, if you are using a plugin GFCI tester it will not trip. This should be obvious. It does not mean the GFCI is not functional.
Scott Shaw
Member
- Location
- Texas
- Occupation
- HVAC & Electrical Contractor
From one of the receptacles down line with my GFCI tester
kwired
Electron manager
- Location
- NE Nebraska
Plug in tester actually subjects it to a line to ground load of enough current that should make it trip. With no EGC there is no place for that current to flow. It still will trip (presuming it works properly) if enough current is flowing anywhere besides between the protected "hot" and "neutral".
acin
Senior Member
- Location
- pacific grove california
- Occupation
- general building contractor est.1984 . C 10 elec. lic.as of 8 / 7/ 2020
Test button with a load?
Scott Shaw
Member
- Location
- Texas
- Occupation
- HVAC & Electrical Contractor
Ok, Thanks everyone!
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
The test button inside the GFCI receptacle itself uses a resistor to bypass current from the hot on the load side to the neutral on the line side. No current needs to flow in the EGC.
Since the plug-in tester does not have access to the line side of the GFCI, it has to divert current somewhere else, and the only place available is the EGC.
If you really want to use a plug-in tester you would have to connect a ground from somewhere to the ground prong of the tester.
GFCI receptacles are specifically listed for use with no EGC present, and that is why a few "No Equipment Ground Present" stickers are included in the package.
kwired
Electron manager
- Location
- NE Nebraska
That is what plug in GFCI testers do, put a load (at least 6 mA) from hot to ground. OP has no ground therefore no complete circuit for any current to flow, GFCI responds to current not voltage.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Thus, the correct response is that a GFCI does not need an EGC to operate, but a plug-in tester does.
Another C10
Electrical Contractor 1987 - present
- Location
- Southern Cal
- Occupation
- Electrician NEC 2020
And an Inspector would shoot it down ..
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
Then you have an opportunity to educate the inspector. There is no basis in this situation for the inspector to reject it.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
I will post a graphic tomorrow that shows why a GFCI does not need a EGC to trip.
Please consider a GFCI circuit breaker does not have a EGC connected, and it trips, but only with the test button
Please consider a GFCI circuit breaker does not have a EGC connected, and it trips, but only with the test button
Another C10
Electrical Contractor 1987 - present
- Location
- Southern Cal
- Occupation
- Electrician NEC 2020
ok then ..
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
A test the inspector could observe would be to use a solenoid tester between the receptacle hot and the ground of an extension cord that is plugged into a grounded receptacle. I've even used plumbing to test against when there's no EGC handy.
ptonsparky
Tom
- Occupation
- EC - retired
Until I learned here that the only way to ’test’ was the button, that was what I did with about all GFCIs. That and TR devices.
kwired
Electron manager
- Location
- NE Nebraska
There are many ways to test. Only one method recognized by instructions.
If introducing real fault current doesn't trip it, chances are the test button won't either. If it does, my suspicions go way up as to whether it is a counterfeit device or not.
ptonsparky
Tom
- Occupation
- EC - retired
I should have inserted a'
' in "the only way to ...."
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
A GFCI does not care if there is an equipment ground or not. It looks at the difference in current between the line and neutral (for a 120V circuit) and trips if the difference exceeds 5 mA.
The best way to test any GFCI is by use of the test button.
synchro
Senior Member
- Location
- Chicago, IL
- Occupation
- EE
The issue with using something like a solenoid tester or the like is that it may verify the GFCI is basically functioning, but it does not confirm it has adequate sensitivity to ground fault leakage.
For a lark I measured a resistance of 14.6kΩ from the line out hot to line in neutral on a Pass & Seymour GFCI when the test button was pushed. So that would apply 8.2 mA of unbalanced current for a 120V input.
A Sperry plug-in tester had 16.6kΩ when the test button was pushed which would apply 7.2 mA with a 120V input.
I couldn't measure a Leviton GFCI because pushing the test button also mechanically trips open the contacts.
For a lark I measured a resistance of 14.6kΩ from the line out hot to line in neutral on a Pass & Seymour GFCI when the test button was pushed. So that would apply 8.2 mA of unbalanced current for a 120V input.
A Sperry plug-in tester had 16.6kΩ when the test button was pushed which would apply 7.2 mA with a 120V input.
I couldn't measure a Leviton GFCI because pushing the test button also mechanically trips open the contacts.
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