In article , wrote:

Intermittent ground in the flaky outlet box? Offhand, you'd think that since
a ground isn't necessary for GFCI operation, you wouldn't need one for testing,
but I'm at a loss (at least until the caffeine kicks in) how one could test
GFCI operation without a ground to fault to...

While that might explain the test button on the GFCI not working, how about
the test button on my plug-in tester? That tripped the GFCI _every_time_.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?