A cable splice assembly includes a tubing encapsulated cable, an electric submersible downhole cable, where the tubing encapsulated cable and the electric submersible downhole cable are tape-spliced through a pair of respective contacts, and a thermoplastic insulator to seal the tubing encapsulated cable. A shell contains the tape-spliced tubing encapsulated cable and the electric submersible downhole cable and multiple layers of sealant tape are wrapped around at least the tubing encapsulated cable and the thermoplastic insulator inside the shell, where a number of layers of the sealant tape is selected to create a pressure blocking seal inside the shell.