As the three-phase meter suggests, the meter used to measure the power of the three-phase supply is known as the three-phase energy meter. In simpler words, the 3-phase electric meter is used for measuring the power of a three-phase electrical supply. The three-phase meter diagram illustrates that the three-phase meter is constructed by connecting the two single-phase meters through the shaft. The total energy is the sum of the reading of both elements. EdrawMax Online comes with free electrical symbols that let you easily create similar-looking diagrams for your home electrical projects.