You don't mention whether other appliances on the circuit also have the
20 minute delay. Many appliances have their own internal safety breaker, and
some of those are temperature/time dependent. Perhaps the breaker that is
taking 20 minutes to reset is inside the microwave, and not the GFI. Does
the whole circuit go off for 20 minutes? When the microwave goes off, does
the GFI reset immediately if you disconnect the microwave? I suspect the
defect is inside the microwave, causing both the 20 minute delay and also
perhaps the GFI fault.
Microwaves are cheap, and a little dangerous to fiddle with. Consider
replacing the microwave.

Dave
"John Grabowski" wrote in message
news
You can try replacing the GFI, but I think you have a problem with your
microwave oven. Try plugging a different appliance into that GFI
receptacle
to see what happens.

John Grabowski
http://www.mrelectrician.tv



"John Bagdanoff" wrote in message
om...
I have a problem with my microwave oven tripping the gfi outlet it's
plugged into. Once the gfi trips, it takes hours until the reset
button 'clicks' & I have restored power to the outlet. I have an
outlet tester with a button to press to trip a gfi outlet. When I use
this to test the outlet, the gfi trips immediately, & I can quickly
rest the gfi outlet.
So my question is, why this long delay in resetting the gfi outlet
when the microwave oven trips it (it trips when I turn on the oven),
versus a quick reset when using my handy dandy tester?

Thanks
John