This study focuses on calculating the electrical properties of composites of CNTs with polystyrene within the framework of percolation theory. Nano-composites, with multiwall carbon nanotubes (MWCNTs) as a filler; especially synthesized in a dc arc plasma system in presence of focusing electric field, have been shown to exhibit metallic behavior. The purity of the MWCNTs prepared under the optimized focusing voltage of 400 V is then seen to be much higher as compared to the one synthesized at zero focusing voltage.