All circuit-breakers series BP type BP1 consist of three poles with vacuum interrupters filled with cast epoxy compound and mounted on the circuit-breaker frame. The circuit-breaker electromagnetic drive fixing circuit-breakers in C and O positions on magnetic latches is housed in the circuit-breaker frame. The core of the electromagnetic drive is connected with the circuit-breaker shaft via connecting links. The circuit-breaker shaft is connected via insulating tie-rods with vacuum interrupters and when turning, it controls circuit-breaker position contacts for external auxiliary circuits. Almost in all circuit-breakers, plate-type pressing springs are installed in insulating tie-rod bushings. Control block schemes are realized by using PCBs housed in circuit-breakers series BP.