A pre-expanded cover assembly for protecting a cable splice connection including a cable, the cable including an electrical conductor surrounded by a cable insulation layer, includes a splice body assembly and a removable holdout. The splice body assembly includes a tubular, cold-shrinkable, electrically insulative, elastomeric splice body having an interior surface defining an interior passage. The splice body assembly further includes a tubular layer of a conformable medium pre-mounted on the interior surface of the splice body. The conformable medium is a flowable material having a high electrical permittivity. The splice body assembly is mounted on the holdout such that the holdout maintains the splice body in an elastically radially expanded state, and the holdout is selectively removable from the splice body to permit the splice body to elastically radially contract. The layer of the conformable medium is positioned and configured such that, when the pre-expanded cover assembly is positioned adjacent the cable splice connection, the holdout is removed from the splice body, and the splice body elastically radially contracts onto the cable splice connection, the layer of the conformable medium will be radially interposed between and engage each of the interior surface of the splice body and an opposing interface surface of the cable insulation.