I installed several GFCI’s throughout the house to bring things up to code. After installation I tested each one per the instructions and indications are they’re all working properly. I then decided to use my Commercial Electric brand plug-in circuit tester as a final check and all but one GFCI tested as it should. The one at the kitchen counter, however, trips as soon as the tester is plugged in, but it doesn’t trip when appliances are plugged in, they all work properly. That particular GFCI loads two (2) other outlets downstream so I disconnected them and ran the test at the GFCI by itself and sure enough, it tripped again. I can plug things into the outlet and they all work fine but plugging the tester in trips it every time. It seems strange that the tester works in all other outlets throughout the house but that one. I even switched GFCI’s thinking maybe it’s a faulty unit but the same thing happens with either GFCI. I verified that the incoming power source (white-black-ground) are properly connected to the LINE terminals on the GFCI.
Right now I’m continuing to use the outlet as I have for the 30 years that I’ve lived here (home built in 1986). It’s just perplexing as to why my tester works properly in all outlets of the house except that one.