A vacuum assembly including a vacuum interrupter may be sealed with a compliant material and/or rubber plugs, so that a cavity is created and maintained within the assembly for use with a current exchange housing and/or bellows, during operation of the vacuum interrupter. During vacuum molding of the vacuum assembly to encapsulate the vacuum assembly in an epoxy, a resulting pressure differential caused by the vacuum molding is prevented from disturbing the seal around the vacuum assembly, by way of a needle or tube included in the seal. In this way, air from within the cavity is allowed to escape, while the epoxy is prevented from entering the cavity. Then, once encapsulation is complete, the vacuum assembly can be joined with an operating rod and other components to complete a vacuum switching device.