Most Pre-insulated Bushings Lack Structural Sealing.

Most pre insulated sleeve connections are primarily formed from insulating material and are attached to external systems via mechanical fitting or heat shrinking, rather than managing interface conditions through integrated sealing rings. This means that at the intermediate layer joint of the pre insulated junction sleeve interface, the sealing properties are more influenced by the surrounding construction conditions and the selected auxiliary materials than by the structural design of the insulated joint sleeve itself.