This product adopts special chips, with the feature of high accuracy, stability and credibility. It meets technical requirements of National Standard of GB/T17882-1999(IEC62053-21-2003. IEC62052-11-2003). Functions and features: 1. Reactive measurement and high accuracy. 2. No need to calibrate in long-term operation, frequency, voltage and harmonics have small influence on accuracy of measurement. 3. To avoid stealing electricity through reverse connection, short-circuiting or adding magnet methods. 4. With power impulse output of coupling isolation, convenient verify and communication. 5. Adopting high quality and high reliability elements 6. When one or two phase is open in the circuit, there is no influence on accuracy. Technical parameter: Relative humidity: ≤ 85% Power loss: ≤ 1W/6VA Accuracy Class: 2.0 Rated Voltage (V): 3 *220/380 Three-phase four wire, 3 *100 Three-phase Three wire Basic Current (A): 3*1.5(6), 3*5(20), 3*10(40), 3*20(80)