Abstract: The operation of energized substation circuit breakers in electrical power distribution systems is directly monitored. For each circuit breaker in a multi-phase breaker arrangement, the flow of electrical current is sensed. A signal is then formed for each phase representative of the sensed current flow. The signals so formed for the multi-phases are combined into a composite waveform for monitoring and diagnostic purposes. In the composite waveform, the signal for each phase of the circuit breaker is identifiable by its time relationship to others and by a distinctive voltage level.