The utility model discloses a breakaway device for on electric power system cubical switchboard, it includes the main part, is provided with energy storage mechanism, actuating section, signal device and contact in the main part, energy storage mechanism includes main shaft and spring position fixing piece, and the front end of main shaft passes spring position fixing piece and antetheca and its end and is equipped with the contact, and screw thread section cover is equipped with power spring and movable nut, and optical axis section cover is equipped with spacing spring, and the front portion of main shaft is equipped with the draw -in groove, the actuating section includes starter motor and drive mechanism, and drive mechanism includes connecting rod, transfer line and excite the separation blade that the one end of transfer line can be made way and made its other end rebound promote to excite the separation blade, and then the messenger excites the separation blade to throw off main epaxial draw -in groove under the drive of connecting rod. The utility model discloses having set up succinct energy storage mechanism, can having pulled the trigger through the remote control receiving ware, overall structure is simple, convenient to use, and small, light in weight makes things convenient for the vehicle -mounted to carry, and easy operation is very practical under emergency.