What's going on here boys?

[Jeffrey R. Pope]

I don't need to know how to report this, I've already done that. For my own information, I'm just curious as to what is going on. I also know that the three-light tester is the least reliable tester, but I'm using it to illustrate this oddity.

The GFCI would open when it's internal test-button was used, but not with any of my testers.

(Pic #1) Plug in the SureTest and get an "open-ground" indication.

(Pic #2) Plug in the three-light tester and get an "open-ground" indication.

(Pic #3) With the three-light tester plugged in, I plugged in my SureTest which now gives me a "reverse-polarity" indication - at the same time, the three-light tester now indicates "normal wiring."

(Pic #4) While testing the GFCI through the SureTest, the three-light tester goes back to the "open-ground" indication.

It didn't matter which tester was on top, the results were always the same.

So what's going on? Is this just simply an "open-ground?"

[Bruce A. King]

Open ground and a shared neutral with the light circuit probably.

The neon lamps in the 3-light tester could be confusing the sure test and vice-versa.

[Jeffrey R. Pope]

I didn't think to flip the switch

That may have something to do with it. All of the switched receptacles in the house showed reverse polarity.

[Pierre Belarge]

The 3 lamp tester is completing the open circuit conductor.

[pdickerson]

The recep. is probably correctly wired as a two wire with no ground. When the three light tester is plugged in, there is a resistance place in series between the hot and the ground prong of the recep. Because the recep. is not grounded, the ground prongs and the other gounded parts are now at 120 volts. The Suretest registers the 120 volt difference in potencial between the neutral and the ground prongs. Result is RP.

I am not sure why the 3 light tester reads normal when testing the GFCI function with the Suretest.