Abstract: A circuit breaker-includes: a casing having a base and a main cover secured to the base, the casing accommodating a circuit breaking mechanism; a recesses formed in one surface of the main cover, the opposite surface of which is on the side of the base, the recess being adapted to receive an auxiliary device of the circuit breaking mechanism; and an auxiliary cover mounted on the main cover in such a manner as to close the recess. The circuit breaker is automatically tripped when the auxiliary cover is opened, thus permitting installation of the auxiliary device thereon with high security.

Abstract: The present invention relates to a circuit breaker with an arc light absorber comprising: a pair of electric contactors contained in an insulating container for opening or closing an electric circuit, electric conductors forming said electric contactors and contacts provided at said conductors, an arc extinguishing plate for extinguishing an arc produced between said contacts when said electric contactors are opened, and a pair of side walls confronting the portion except the locuses drawn by said contacts when said contactors are opened and closed at the position of the arc extinguishing plate side of said locuses to form an arc light absorber, said side walls formed of a composite material having one or more of fiber, net or porous material having more than 35% of porosity and the arc produced between said contacts being discharged through between said pair of confronting side walls.

Abstract: A circuit breaker with an arc light absorber comprising: a pair of electric contactors contained in an insulating container for opening or closing an electric circuit, and having electric conductors and contacts provided on said conductors, and a pair of side walls on both sides of said contactors at positions for covering all the locuses of said contacts when said contactors are opened or closed, said side walls being formed of a composite material having one or more of fiber, net or porous material having more than 35% apparent porosity.

Abstract: The present invention relates to a circuit breaker with an arc light absorber comprising: a pair of contactors contained in an insulating container for opening or closing an electric circuit, electric conductors forming said electric contactors and contacts and arc runners provided at said conductors, and arc light absorbing side walls provided at both sides of said arc runners for absorbing the arc light energy irradiated directly to the arc produced between said contactors, said side walls being formed of a composite material having one or more of fiber, net or porous material having more than 35% of apparent porosity.