An insulating system for splicing a pair of cables having at least partially exposed non-insulating portions joined with a metallic connector is disclosed. The insulating system includes an insulating tube constructed from a shape memory material having a central section having a substantially elliptical cross-section and a pair of end sections with substantially circular cross-sections. A pair of support cores is removably insertable in each of the end sections for holding the end sections in a stretched configuration. When the insulating system is placed about the cables and the connector and the support cores are removed from the end sections, the end sections return to a pre-stretched configuration, thereby completing a splice of the cables.