Method for monitoring circuit breaker and apparatus and internet of things using the same

A method and system for monitoring condition of a fleet of circuit breakers includes: measuring at least one type of operating condition related signal for the respective circuit breakers during their operation; obtaining a set of feature data representing the respective measurements of operating condition related signal; performing cluster analysis of the set of feature data based on a similarity threshold; and generating a signal indicating the condition of the fleet of circuit breakers based on the resulting cluster number. Rather than comparing the data representing the measurements of operating condition related signal to a reference model built on CB's normal data, the method includes applying cluster analysis of the set of feature data representing the respective measurements of operating condition related signal. The method does not need a reference "normal" database for comparison.