this disclosure teaches a suspension insulator comprised typically of a fiberglass rod with mounted metal hardware at each end and juxtaposed polymer sheds strung thereon , which insulator has been improved for high voltage application . above system voltages of about 138 kv , undesirable radio noise and corona occurs in the area of the metal hardware in conventional designs . addition of semiconducting polymers between the metal hardward and the polymer sheds significantly reduces the level of generated radio noise and eliminates the corona .