US 110V GFCI outlet and one downstream outlet work fine, other downstream outlet shows "Open Ground", works but does not trip

Question

A GFCI outlet recently stopped working so I replaced it myself. This GFCI outlet is connected to another standard outlet and a third outlet which is more like a strip.

• A GFCI tester on the GFCI outlet and the first standard outlet shows that the wiring is correct, and trips when the test button is pressed.
• On the third outlet, I get power flowing, but I get the lights for "Open Ground" on the GFCI tester and the test button on the GFCI tester does not trip at all.
• However, when I press the test button on the GFCI tester, I get the lights indicator for "Hot/Neutral Reversed."

I believe I wired the GFCI outlet correctly, but what should I be looking for? I only changed the GFCI outlet, but did not touch the other two outlets.

Answer 1

A GFCI tester depends on a working ground to test the gfci functionality. If does this by connecting a resistor across live and ground to induce a ground fault, which if ground is not connected looks like live and ground are at the same potential instead of neutral and ground as it should be.

If you cannot figure out the ground connection, then this setup is an allowed configuration assuming you mark every protected outlet without working ground with "no equipment ground" in addition to the "GFCI protected" I'm sure was already there from when the original GFCI was installed.

Answer 2

There should be a green or bare ground wire which connects to every receptacle, unless you have individual wires in metal conduit. That ground wire is either not connected or connected improperly somewhere. That could either be at the last "good" receptacle or at the "bad" receptacle.

With cables (as opposed to individual wires in conduit), most of the time the ground is connected using the bare wire in each cable to the receptacle ground screw (whether GFCI or not). However, if you have metal boxes instead of plastic and good quality receptacles (should be any GFCI/receptacle, and better quality plain receptacles) and ground wire connected to the metal box then the receptacle ground will be connected automatically via the metal yoke of the receptacle touching the metal box. In addition, sometimes (in my old house at least) the bare ground wire is connected on the outside of a metal box but still provides a good ground to the box and to the receptacles via the yoke - but you don't see any ground wire inside the box.