Ungrounded gfci receptacle won’t test

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Stevenfyeager

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United States, Indiana
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electrical contractor
Ungrounded gfci outlets sometimes don’t test with a handheld tester but test ok with the test button. In older homes in jurisdictions here we are allowed to install gfci receptacles on ungrounded circuits and use grounded 3- hole outlets downstream which is what these home buyers want. I have only one city inspector in the area that won’t pass this, because his handheld tester won’t trip the gfci receptacle even though the test button does. Is there an NEC section that addresses this? Thanks
 
Stevenfyeager said:
Ungrounded gfci outlets sometimes don’t test with a handheld tester but test ok with the test button. In older homes in jurisdictions here we are allowed to install gfci receptacles on ungrounded circuits and use grounded 3- hole outlets downstream which is what these home buyers want. I have only one city inspector in the area that won’t pass this, because his handheld tester won’t trip the gfci receptacle even though the test button does. Is there an NEC section that addresses this? Thanks
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The NEC allows a 3-prong receptacle without an EGC to be GFCI protected. It won't trip with a plugin tester because that tester requires an EGC to work. The only approved testing method is the test button. The inspector is wrong.
 
And if logic and physics won't work on the inspector, and he requires seeing his tester trip, and you want to appease him, you could do this:

You'd need access to an actual EGC from any circuit, or a neutral from a circuit that is upstream of the GFCI device. Plus one of those 3-2 prong adapters with the little lug for an external ground. Run a wire from that lug to the EGC or the upstream neutral, and then plug in the tester through the adapter. That will provide a complete circuit when the tester's button is pressed, and it should trip the GFCI.

Cheers, Wayne
 
Stevenfyeager said:
Ungrounded gfci outlets sometimes don’t test with a handheld tester but test ok with the test button. In older homes in jurisdictions here we are allowed to install gfci receptacles on ungrounded circuits and use grounded 3- hole outlets downstream which is what these home buyers want. I have only one city inspector in the area that won’t pass this, because his handheld tester won’t trip the gfci receptacle even though the test button does. Is there an NEC section that addresses this? Thanks
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If this is the same inspector you were talking about in this thread you haven't had made any headway in training him.

It is not an NEC issue, it is the way the circuit and tool work.

Roger
 
roger said:
It is not an NEC issue, it is the way the circuit and tool work.

Roger
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If the inspector doesn't learn about how the circuits and tools work then he doesn't understand why the code allows this use. All I can do is shake my head and share my condolences. That's really unfortunate and my sympathy goes out to the OP.
 
Did you put the label "No Equipment Ground" on these receptacles or their cover plates as stated in 406.4(D)(2)(b) for the GFCI and their downstream receptacles as in 406.4(D)(2)(c) ? Adding such labels should clarify the ungrounded status of these receptacles if the labels are not already in place. And with no equipment ground present the plug-in tester will not work

If the inspector does not understand the limitations of his tester, I suggest the following:
Ask the inspector to give you his tester so that you can measure the resistance between its ground and line (hot) pins with your meter when you have the test button pushed in. I should read about 15 to 16 Kohms. Then show that it's an open circuit when the button isn't pressed. Hopefully that will allow him to understand that his plug-in tester requires an equipment ground to operate. But 406.4(D)(2) provides an allowance for having no equipment ground, in which case his tester cannot work.

Also, OSHA has this on their webpage linked below:

"How to Test the Operation of a GFCI
The Office of Electrical, Electronic, and Mechanical Engineering Safety Standards does not recommend the use of GFCI testers as a means of determining compliance with §1926.404(b)(1)(ii), as such testers may not produce accurate results. Ground-fault circuit interrupters incorporate a testing circuit that can be used to determine whether or not the device itself will function as intended. No further tests are necessary."

https://www.osha.gov/laws-regs/standardinterpretations/1992-02-10
 
To add, the reason the test button on a plug-in tester doesn't work with no EGC is:

A GFCI device has access to both line conductors within the device, and mimics a shock by connecting a resistor to the hot wire after the sensor to the neutral ahead of the sensor.

A plug-in tester only has access to both line conductors after the sensor, so can only mimic a shock by connecting its internal test resistor between the hot wire and the circuit EGC.

For those dealing with (home) inspectors who use a plug-in tester: Use a grounding "cheater" and extend the green wire with an alligator clip on the other end, clipped to a ground.
 
See page #8 which shows how the 15K ohm internal test resistor works. At 120 volts and 15K ohm the unbalance would be: 120/15,000 = .008 Amp (8 milliamp), which trips the relay. GFCI info Link
 
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