Patent ID: 8530775

Claim:
A pole part of a switching device comprising: a vacuum interrupter chamber having a fixed contact and a movable contact, the movable contact having an electrical connection piece; a drive rod configured to drive the movable contact of the vacuum interrupt chamber; an insulating casing constituted by an insulating material into which the vacuum interrupt chamber is cast, the insulating casing having an opening at a bottom portion in at least one of a region of the movable contact and the drive rod; and at least one ventilation opening formed in at least one of the region of the movable contact and an articulation point of the drive rod, wherein the electrical connection piece extends through the insulating casing and is connectable to a contact external to the insulating casing; and wherein the at least one ventilation opening is formed to pass through at least one of a wall of the insulation casing, a boundary zone between the insulation casing and the electrical connection piece of the movable contact, and the electrical connection piece of the movable contact.