Abstract: Wellhead electrical connection apparatus for feeding electricity into a well under fluid pressure, includes a mandrel sleeve having an internal sleeve shoulder formed to face high pressure end of sleeve. A performed rigid high mechanical strength dielectric insulator support having an external insulator shoulder is installed within the sleeve with the insulator shoulder in abutment with the internal shoulder of sleeve. Insulator support means is mounted and sealed in physically bonded relation within the interior of the sleeve by means of dielectric potting material disposed as an insulator film or sleeve in surface areas between insulator support and sleeve. Insulator support has a plurality of holes extending in parallel and laterally spaced apart relation through the insulator with each hole having an internal hole shoulder formed to face high pressure end of sleeve.