GFCI test button

[TVH]

Electrical and Safety Professionals have told me that the test button on GFCI receptacles is a test of the mechanical mechanism "only" and does not actually cause a ground fault. I'm also told that "portable GFCI /circuit testers" actually cause a ground fault and these devices should be used by inspectors to confirm the proper operation of a GFCI as well as proper wiring. Would appreciate clarification on this important issue by you folks in the field.

 

[charlie b]

I believe you have been misinformed. The test button on the GFCI receptacle causes current to flow from the ungrounded ("hot") conductor to the grounded ("neutral") conductor. The GFCI device will then recognize the imbalance between the two conductors and this will result in a trip. The portable GFCI tester will cause current to flow between the ungrounded conductor and the equipment grounding conductor (the green wire). This will also result in a trip. But it will not work if there is no green wire in the circuit. The NEC does allow an ungrounded receptacle outlet that has no ground wire available to the outlet box to be replaced with a GFCI receptacle (you must label the outlet "no equipment ground"). So the GFCI receptacle can be functioning correctly, but a portable GFCI tester will not be able to discern that. The test button on the receptacle itself is the most reliable way to verify that the receptacle is operational.

 

[roger]

Electrical and Safety Professionals have told me that the test button on GFCI receptacles is a test of the mechanical mechanism "only" and does not actually cause a ground fault. I'm also told that "portable GFCI /circuit testers" actually cause a ground fault and these devices should be used by inspectors to confirm the proper operation of a GFCI as well as proper wiring. Would appreciate clarification on this important issue by you folks in the field.

As Charlie explained, what you have been told is basically in reverse as to what's true. As a matter of fact, for a long time and I think it's still true the only UL recognized way of testing a GFCI device was with the on bard test button.

Roger

 

[Dennis Alwon]

I will also add that the gfci tester will not trip a GFCI receptacle or circuit if there is equipment grounding conductor.

 

[ActionDave]

I will also add that the gfci tester will not trip a GFCI receptacle or circuit if there is equipment grounding conductor.

I think you meant if there is no egc.

 

[charlie b]

I think you meant if there is no egc.

I sure that is what he meant. I am also sure he also intended to credit me with having already said that in my earlier post. :happyyes:

 

[Coppersmith]

I have an Ideal 61-165 tester I use for testing GFCI's. It seems to catch many bad GFCI's that don't show as bad when the GFCI's test button is actuated. Does my tester work the same as the GFCI testers you are talking about? I'm assuming you are talking about those cheap ones with the three neon lights in them.

 

[don_resqcapt19]

I have an Ideal 61-165 tester I use for testing GFCI's. It seems to catch many bad GFCI's that don't show as bad when the GFCI's test button is actuated.

What makes you think that your tester is correct and the device test circuit is not?

Does my tester work the same as the GFCI testers you are talking about?

All plug in GFCI testers work the same way. They actually create a ground fault and they can only do that if the receptacle being tested has an EGC that provides a path back to the main bonding jumper.

 

[GoldDigger]

What makes you think that your tester is correct and the device test circuit is not? All plug in GFCI testers work the same way. They actually create a ground fault and they can only do that if the receptacle being tested has an EGC that provides a path back to the main bonding jumper.

Or if you supply a temporary return connection via an external EGC to another point in the wiring system.
I would not recommend trying to use a foreign neutral connection instead.

 

[roger]

I have an Ideal 61-165 tester I use for testing GFCI's. It seems to catch many bad GFCI's that don't show as bad when the GFCI's test button is actuated. Does my tester work the same as the GFCI testers you are talking about? I'm assuming you are talking about those cheap ones with the three neon lights in them.

I have a GFCI tester that cost over a hundred and twenty five dollars (I have it for testing hospital Isolation systems) and it is no more a true GFCI test than a 5 dollar unit can do. IOW's, use the on board test button if you want a correct test.

Roger

 

[roger]

Or if you supply a temporary return connection via an external EGC to another point in the wiring system.

Temporary or permanent, that is exactly what Don said.

Roger

 

[kwired]

The test button does make the device see same condition as seen during a ground fault, but without an actual ground fault.

A resistor sized to draw enough current to be in the trip range of the device is connected with one lead through the current sensing CT and the other lead does not pass through, which unbalances the current in the CT and causes the device to trip if the electronics are functioning correctly. This is why the test button will trip the device even if there is no EGC present. A plug in tester must have an EGC or at least have EGC connected to a path that will carry the needed 4-6 mA to cause the device to trip.

 

[TVH]

Electrical and Safety Professionals have told me that the test button on GFCI receptacles is a test of the mechanical mechanism "only" and does not actually cause a ground fault. I'm also told that "portable GFCI /circuit testers" actually cause a ground fault and these devices should be used by inspectors to confirm the proper operation of a GFCI as well as proper wiring. Would appreciate clarification on this important issue by you folks in the field.

Thank you gentlemen. Very informative.