A circuit breaker comprising: a light source for emitting light; an optical sensor for detecting light emitted by the light source ; a handle movable between different handle positions which correspond to different circuit breaker statuses, the handle including a handle body and a light control plate which moves along with the handle body , the light control plate having different light passage regions (210A-C, 610A-C, 710A-C) each of which is configured to be positioned between the light source and the optical sensor when the handle is moved to a corresponding one of the different handle positions, each of the different light passage regions (210A-C, 610A-C, 710A-C) allowing a different amount of light emitted from the light source to pass to the optical sensor when positioned between the light source and the optical sensor ; and a processor configured to determine a status of the circuit breaker based on the sensed amount of light which relates to a position of the handle , wherein the light control plate extends from the handle body , the circuit breaker further comprising: an interior wall having opposing sides and a guide channel extending through the opposing first and second sides, the light control plate having a portion extending through the guide channel from the first side of the wall facing the handle body and being movable along the guide channel with movement of the handle , the optical sensor and the light source being connected on opposite sides of the guide channel on the second side of the wall ; and a case for housing circuit breaker components including the interior wall . a light source for emitting light; an optical sensor for detecting light emitted by the light source ; a handle movable between different handle positions which correspond to different circuit breaker statuses, the handle including a handle body and a light control plate which moves along with the handle body , the light control plate having different light passage regions (210A-C, 610A-C, 710A-C) each of which is configured to be positioned between the light source and the optical sensor when the handle is moved to a corresponding one of the different handle positions, each of the different light passage regions (210A-C, 610A-C, 710A-C) allowing a different amount of light emitted from the light source to pass to the optical sensor when positioned between the light source and the optical sensor ; and a processor configured to determine a status of the circuit breaker based on the sensed amount of light which relates to a position of the handle , wherein the light control plate extends from the handle body , the circuit breaker further comprising: an interior wall having opposing sides and a guide channel extending through the opposing first and second sides, the light control plate having a portion extending through the guide channel from the first side of the wall facing the handle body and being movable along the guide channel with movement of the handle , the optical sensor and the light source being connected on opposite sides of the guide channel on the second side of the wall ; and a case for housing circuit breaker components including the interior wall . an interior wall having opposing sides and a guide channel extending through the opposing first and second sides, the light control plate having a portion extending through the guide channel from the first side of the wall facing the handle body and being movable along the guide channel with movement of the handle , the optical sensor and the light source being connected on opposite sides of the guide channel on the second side of the wall ; and a case for housing circuit breaker components including the interior wall . <EOS>