A digital power metering system with serial peripheral interface (SPI) multimaster communications is provided. A digital power meter is provided that includes at least one sensor that senses analog electrical parameters on electricity transmission lines from an electrical power distribution system, at least one analog-to-digital converter that receives the analog electrical parameters from the at least one sensor and converts the analog electrical parameters to sampled data; at least one processing device that performs calculations to determine power usage based on the sampled data and control overall operation of the meter, and a Serial Peripheral Interface (SPI), wherein the at least one processing device includes a plurality of processing devices, the SPI allowing one of the plurality of processing devices to become a master and the other processing devices of the plurality of processing devices to become slaves.