As a replacement for porcelain and glass, two fundamental polymer compositions—silicone rubber (SiR) and ethylene propylene diene monomer (EPDM)—as well as a combination of these two compositions—have been used for outdoor electrical insulation applications. There is widespread agreement that improving a composite's insulating properties by adding micron-sized particles is possible. To enhance these composites when used for outdoor electrical insulation, various fillers such as alumina trihydrate and silica are used. In this study, the effect of micro filler Silica with various contents on the electrical and mechanical properties of blending of SiR and EPDM with different weight ratios was studied. Test samples were prepared using two roll mill. To analyze the electrical characteristics, AC breakdown tests were conducted following IEC 60243-1 Standard. Tensile strength and elongation at break were carried out according to ASTM D-412 for assessing the mechanical properties. This experiment demonstrates an increase in dielectric breakdown strength of all EPDM/SiR composites filled with Silica micron particles till 30 Phr filling content behind this value the breakdown strength was decreased. Regarding mechanical parameters, the micro silica composite exhibited enhanced Tensile Strength to till only 10 Phr, contrarily, doping micro silica deteriorates the Elongation at break for all microcomposite samples.