Abstract: Provided is a power measuring system for measuring power of a main circuit of incoming feeder and a branch circuit in a distribution panel, cabinet panel, or motor control center. The power measuring system includes a voltage sensing unit for sensing analog voltage of the main circuit and generating main voltage data by converting the sensed analog voltage to digital form, a current sensing unit for generating main current data of the main circuit or sub current data of the branch circuit, and a current data communication unit or voltage data communication unit for transmitting the sensed data or power-related data generated using the sensed data, wherein main circuit power data or branch circuit power data is calculated and displayed or transmitted.