Chuck,

It could have been an anomoly. More likely however is the circuit breaker is old and tired, or there is a glitch causing it to trip.

The circuit breakers are quite common so if it trips again, go to WW Grainger or equivalent and get a replacement and install it. If the new one trips you have an internal inverter problem. The CB trip could have been caused by something as simple as overloading the circuit (DUH!).