A locking apparatus for a circuit breaker includes a locking pin including a main body; a rotatably or displaceably mounted definition tip; and a guide including a mating contour. In an embodiment, the locking pin is movably mounted within the guide. The definition tip is in alignment with the locking pin in a first position, such that the locking pin together, with the definition tip, is movable through the guide. Further, the definition tip cannot be moved through the guide in a second position, owing to the deflection of the rotatably and displaceably mounted definition tip of the locking pin.