This study focuses on characterization of silicon carbide (SiC)-epoxy nanocomposites with different mass loading of SiC using different techniques to evaluate the physicochemical, thermo-physical and surface discharge activity of the insulating materials. A marginal increase in surface discharge inception voltage (SDIV) was observed with increase in wt% loading of SiC in the epoxy but not much variation is observed with increase in supply frequency. Surface discharge process radiates electromagnetic waves in the UHF signal frequency range of 0.5–1.5 GHz. The dielectric properties of the material get altered with the percentage of SiC material in epoxy resin. TEM analysis indicates uniformity of dispersion of nano particle in epoxy resin. Charge retention capability of the material is high when the deposited charges are unipolar. Optical emission studies indicate the presence of silicon peaks with SiC-epoxy nanocomposites in wavelength range of 350-400 nm. Oxygen peaks were observed for all samples. Using the spectral peak positions and intensities of the peaks obtained, the plasma temperature for SiC-epoxy nanocomposites was estimated to be c.a. 2240 K low when compared to that for pure epoxy. LIBS spectra clearly indicate an increase in carbon intensity with corona damaged specimen. Also for the same level of fluency, the amount of damage is less with higher percentage of SiC included epoxy nanocomposites. Pyrolysis GC/MS study indicates that the presence of SiC in the epoxy matrix enhances the timescale of primary pyrolysis vapors such as bisphenol components to form more monomeric phenols via secondary cracking reactions. POLYM. COMPOS., 39:3268–3279, 2018. © 2017 Society of Plastics Engineers. © 2017 Society of Plastics Engineers