Glaze to pin connection for a high voltage direct current insulator with embedded metal fitting

In an electrical insulator for use on positive polarity direct current transmission lines comprising in combination:

• a suitably contoured porcelain shell with a conventional insulating glaze;
• a metal cap and a metal pin each situated at a surface of the porcelain shell opposite to the other, the porcelain shell forming a pin recess receiving the pin;
• capping means securing mechanically the cap to the shell;
• and
• Portland cement in the recess and about the pin securing mechanically to the shell the pin located in the recess;
• wherein, the improvement comprises a conductive carbon-filled phenolic polymer composition which bonds to the cement and to the glaze on the porcelain shell and to the pin, the composition having long-term weather resistance and forming an electrical connection between the pin and the glaze and substantially sealing the Portland cement from contact with moisture in the air, the phenolic polymer composition having a nonionic electrical conductivity substantially greater than the conductivity of the Portland cement.