Base materials for heat-resistant cable insulant have been developed from blends of ethylene vinyl acetate (EVA) copolymer containing 28% VA and ethylene propylene diene (EPDM) rubber. Different electrical, mechanical, and thermal properties of these blends have been studied extensively. Aging under different conditions has also been studied. The chemical and mechanical stability of these compositions has been assessed at the actual temperature range of application. Dielectric properties have been determined against varying temperature. These blends may be used as insulating materials having a temperature rating around 90-130-degrees-C, which is above the temperature rating (85-90-degrees-C) of heat-resistant insulation based on EPDM.