I have a circuit protected by a GFI outlet. The circuit starts in a
downstairs bathroom, runs through a GFI outlet there, then heads
upstairs to a couple other bathrooms. The GFI outlet downstairs has
power, and the circuit breaker trips fine if you hit the test button.
The outlets in the upstairs bathrooms are all dead.

Last week, some carpet cleaners came while I was out of town. I
understand they had some kind of power trouble during their work (i.e.
they thought they had tripped a breaker). Turns out, they did not trip
a breaker in the box - nor were any of the GFI circuits that I know
about in the house tripped.

The strange thing is this... I get my handy voltmeter out, and the
"dead" outlets in the upstairs bathrooms all read 96 volts AC. I plug
in a night light, turn it on, and the voltage drops to zero. I
measured the voltage coming into the GFI outlet downstairs at 120
volts. I read the voltage leaving the GFI outlet downstairs at 120
volts. Upstairs, it's down to 96 volts. If I trip the GFI breaker and
test the outlets upstairs, they all read zero volts. So I'm pretty
darned sure this is all the same circuit.

What ever is wrong with this picture?

- David