Yes and no. I don't have a main breaker, but I can turn off each individual circuit breaker (there are only 10 of them).

The results would be inconclusive unless the meter did continue to turn, because if the meter stopped it would only indicate that the extraneous circuit (if there indeed was one) was not at that moment drawing power.

It's an excellent suggestion, though, and I am going to try it right now.

OK, I had an aha! moment when I found the meter still turning with all my breakers off. Then I realized that the neighbor's breakers go through the same meter, and when I switched all of hers off, the meter stopped.

Doesn't prove anything...

tanstaafl.