The invention belongs to the field of power metering devices which employ an intelligent control technology and realize an automatic control and information transmission technology, and particularly relates to an automatic combined wiring instrument. The wiring instrument is characterized in that by comprising a hardware system and a software system; the hardware system consists of the four parts of an automation part, a simulation detecting part, a function executing part and a power supply part; the software system consists of the two parts of a monitoring program and a function program. The wiring instrument has the advantages that the wiring instrument has the functions of preventing a current transformer from being open-circuited and preventing a voltage transformer from being short-circuited and has the functions of site ammeter examination, regular alternated locking and meter-free billing and timing; the work efficiency is increased by seven times, and the work safety, and the technology and application level of professional site work equipment for power metering are improved; the secondary manual open-circuit of the current transformer and the secondary manual short-circuit of the voltage transformer are completely avoided; the site work efficiency is greatly improved, the labor cost is reduced, and the work time is shortened.