Three-phase four-wire combined junction box capable of changing meter without power failure

The three-phase four-wire combined junction box comprises a junction box main body and a protective cover, wire inlets are arranged on the outer walls of the front side and the rear side of the junction box main body, a mounting groove is arranged on the upper surface of the junction box main body, and a plurality of wire inlet connecting ends and wire outlet connecting ends are arranged in the mounting groove. First compression springs are connected to the front ends of outgoing line connecting ends connecting voltage phase lines and current incoming lines, sliding blocks are connected to the front ends of the first compression springs, the outer walls of the front sides of the sliding blocks are in contact connection with the outer walls of the rear sides of the incoming line connecting ends, connecting columns are inserted into the upper portions of the sliding blocks, and movable plates are fixedly connected to the upper ends of the connecting columns. Left and right ends of the movable plate are slidably