CIRCUIT BREAKER

摘要

A circuit breaker comprising a crossbar (7) supported rotatably on a base (1 B) while holding a movable contactor (4) rotatably, in which the size can be reduced while limiting decrease of over travel with time. The flexural modul i Eb, Ec of the base (1B) and crossbar (7) at normal temperature and humidity satisfy following relations: Eb+Ec>=17000 Mpa.. (1) 8000 MPa<=Eb.. (2) 9000 MPa<=Ec.. (3)