Exemplary embodiments are directed to a circuit breaker arrangement for medium voltage to high voltage applications. The circuit breaker includes at least one pole part housing for accommodating a vacuum insert, within which a pair of corresponding electrical contacts is coaxially arranged. A fixed electrical contact is electrically connected to an upper terminal of the pole part housing and an axial movable electrical contact is electrically connected to a lower terminal of the pole part housing and is operated by an insulating pushrod. The insulating pushrod extends through a shielding plate arranged on a lower opening of the pole part housing. The shielding plate includes a rigid moulded plastic insulating material. At least one sealing ring has an elastic material moulded on the periphery of the shielding plate.