The quest for improved polymeric insulation to achieve a compact and reliable electrical and electronic power equipment design brings about the idea of composite polymeric insulation. Emphasis has been on chemically synthesised metal oxide nanoparticles. This paper presents the dielectric behaviour of epoxy polymer composite with microparticles with an average particle size of about 4.3 μm from the periwinkle shell. The changes in the relative permittivity and dielectric loss of the polymer with the periwinkle shell composite metal oxides at low filler concentrations were studied over a frequency range from 200 Hz to 100 kHz. The results showed that the polymer composite exhibits dielectric characteristics that are quite different when compared with the earlier observed results for polymer micro-composites. Unlike the usual expectations of increasing dielectric loss with increasing filler concentration in polymer micro-composites, the dielectric response of the epoxy-shell microparticle powder composite displayed a decrease in the dielectric loss with micro-filler concentration. The 1 wt% periwinkle shell microparticle epoxy composite has a dielectric loss lower than that of 0.5 wt% Al2O3 nanoparticle epoxy composite. This suggests that the waste periwinkle shell can serve as a cheap resource to produce low-cost polymer composite with improved electrical insulation properties.