Polymer outdoor insulators are widely replacing the conventional ceramic and porcelain insulators due to their compelling properties. This work, studies and compares the mechanical performance of an elastomer matrix, nano and micro filler reinforced, thermoset composite, EPDM Silicone rubber filled with Garamite nano clay and Micro Silica/Alumina Trihydrate, for their applicability as an outdoor insulator. The base composition used for the study is a 50–50 Ethylene Propylene Diene Monomer (EPDM) and Silicone rubber blend. The compatibilizer used in this study is Vinyl Trimethoxy Silane. The strength and weight are important parameters which are looked at, while choosing the material for the outdoor insulator application. Organic nanofillers due to their compact packing have been observed to improve the strength of rubber composites to a great extent even when added in small proportions. This paper discusses the variation in strength of the composite with varying concentrations of Garamite (organic nanoclay). Also, to understand its effect on composite, the concentrations of micro fillers such as Alumina Trihydrate and Fumed Micro Silica which yield comparable strength to that of Garamite are studied. The study reveals that there is not much variation in strength between ATH and Micro Silica fillers, while a distinct difference in strength is observed in the case of the composite with Garamite. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.