Considerable cause of the condensation mechanism of moisture and fog on the contaminated high-voltage insulator surface is the temperature difference between the insulator surface and the dew point which eventuate owing to the mechanism of radiative cooling. Condensation of moisture leads to creating a conducting path on the insulator surface and make the insulator to be a conductor and results in the electrical transmission line failure. In order to cover the above-mentioned temperature difference, carbon nanotubes (CNTs) are being applied to the silicone rubber which is the insulator housing material. This study is based on joule heating generation which decrease the electrical resistance of the high-voltage insulator surface. An advanced mathematical model which is based on Pukanszky formulation for estimation of composite tensile strength was presented for the effectual electrical conduction of silicone rubber - carbon nanotube nanocomposite (SCNT). SCNT samples were produced by the addition of dissimilar CNT concentrations to a high temperature vulcanizing (HTV) silicone rubber by solution-blending method. Comparison between experimental results and theoretical forecasts showed an excellent agreement. The obtained model disclosed that the lower ranks of tunneling resistivity and distance, the higher magnitudes of tunneling diameter, the higher concentration of longer and thinner CNTs, lower CNT curliness, higher fraction of networked CNTs, and deeper interphase can produce the maximum level of SCNT conductivity.