Selective protective breaker

The invention discloses a novel selective protective breaker. A main circuit of the novel selective protective breaker is formed by serially connecting an electromagnetic device, a main contact device and a main circuit current release; a branch circuit is formed by serially connecting an auxiliary contact part, a branch circuit current release and a current limit resistor; two ends of the branchcircuit are respectively connected in parallel with two ends of the main contact device of the main circuit; and an operation mechanism not only can manually control the simultaneous closing/breakingof the main contact device and the auxiliary contact part, but also can operate the simultaneous breaking and tripping of the main contact device and the auxiliary contact part under the control of the main circuit current release and/or the branch circuit current release. When the main circuit is overloaded and exceeds a long delay threshold, the main circuit current release controls the operation mechanism to trip and make the breaker trip. When the main circuit has a short-circuit fault and exceeds a short delay threshold, the branch circuit current release controls the operation mechanismto trip and make the breaker trip. The breaker has more compact and reasonable structure, stronger performance, better reliability and lower production cost.