The sensor is designed according to the European Union CE standard. The outer casing is made of flame retardant material. The input end, the output end and the power end are separated by two, which has high safety. The sensor can measure single-phase AC voltage, current, frequency, active power, reactive power, apparent power, power factor, active energy, reactive energy, and 1-21 voltage and current harmonic content, and output power by digital communication. Parametric, very cost-effective.