Abstract: Under certain special load properties, the phasor characteristics of voltage and current will change, deviating from the correct wiring phasor characteristics, and even approaching the characteristics of some typical miswired phasor diagrams, which are easily misjudged as miswiring. This article analyzes a case of misjudged wiring anomaly caused by a special load property in an electric energy metering device, and studies the graphical characteristics and occurrence mechanism of the metering device wiring phasor diagram under the influence of special loads of intermediate frequency furnaces, to avoid misjudgment of wiring anomaly by metrology personnel and improve the efficiency of wiring inspection.