I replaced a non-protected receptacle with a GFCI type and now my circuit tester trips the GFCI as soon as it is plugged in. The receptacle tested fine before replacement, ground, neutral, hot, etc. I've double checked the hot/neutral/ground connections. I've also tried it with the downstream load disconnected.
The GFCI trips the moment I plug in my circuit tester (before pushing the test button). Otherwise things check out OK. I can plug in a power tool without it tripping. Also, the integrated test/reset button work correctly.
I've read that the integrated test button is the only one that truly matters. Is this correct or should I be concerned? I'm sure a home inspector will red flag this if their tester has the same result.
Update
My tester is by "Commercial Electric". The tester is one of the palm sized three prong type with three leds to indicate the condition of the circuit and a button on top to test GFCI. It's new from the local box store.
Best Answer
As well it should.
Normally, loads are connected between hot and neutral. Appliances are not supposed to connect hot or neutral to ground; ground is only a shield.
The GFCI compares current on the hot and neutral wires. They should be the same. If they are not, current has found another route, possibly through the grounding system (which isn't supposed to happen) and potentially through some poor human.
Circuit testers are trying to test whether ground is connected... cheaply. They mis-use "hot" as a power source, by connecting a light bulb between hot and ground. If ground is connected correctly, this will light.
In other words, it intentionally creates a hot-ground fault (by sticking a light bulb there). This is exactly the condition GFCIs are designed to detect.
I'm not talking about any ground-fault-test the tester may also have.
So why do testers often work? With a perfect GFCI, they wouldn't work. I suspect it is because GFCI's have detection thresholds above zero, and that is often enough for these testers to "get away with it". I even think there may be a tacit agreement among manufacturers for this, but obviously, lower sensitivity impinges safety. Remember a shock which only stuns you can kill you with secondary effects like falling or drowning.
So either your GFCI is pretty good, or your tester is pretty bad.