Cover plate and circuit breaker

A cover plate and a circuit breaker relate to the technical field of low-voltage apparatuses. The cover plate comprises a cover plate body, the cover plate body is provided with a first edge, a second edge and a third edge, the first edge and the second edge are opposite, the third edge is connected with the first edge and the second edge, and a first side edge rib, a second side edge rib and a rear end rib are arranged at the positions, on the first edge, the second edge and the third edge, of the upper surface of the cover plate body respectively. And the first side edge rib, the second side edge rib and the rear end rib are respectively used for being inserted into a circuit breaker shell. According to the cover plate, the rear end rib, the first side edge rib and the second side edge rib are respectively arranged at the rear end, the left side and the right side of the cover plate body and are oppositely inserted with the circuit breaker shell, so that the circuit breaker meets the ground insulation requi