SPECIFICATION:Used for AC three phase four wire active energy measuring. DIN rail installation type, compact ... active+negative activeDisplay data function even after power off (option)Multi-tariff measuring function: Setup T1, T2, T3 and T4 four ... )A Reference frequency:50Hz, 60HzStarting current: 0.004IbConnection type choice: three phase four wires, up in down out,L1,L2,L3,N ...