Abstract: When the polarity of the secondary side of the voltage transformer in a three-phase three wire electric energy metering device is reversed, it is often easy to misjudge the type of abnormal wiring due to possible problems such as abnormal phase sequence judgment of the meter's own voltage wiring. This can further interfere with wiring corrections and even cause new wiring errors. The article studies the abnormal characteristics and principles of this type of abnormal wiring. And propose a judgment method for this type of abnormal wiring. Assist metrology personnel in accurately identifying types of anomalies. Support on-site defect elimination and improve the accuracy of measurement business work.