An electromagnetic shield apparatus is provided for an existing electrosurgical unit (ESU) including a pencil assembly and return pad assembly. The pencil assembly includes a pencil, pencil-assembly cable and terminal couplable to the ESU, and the return pad assembly includes a return pad, return-pad-assembly cable and return-pad-assembly terminal couplable to the ESU. The electromagnetic shield apparatus includes an electrically-conductive shield, a low-impedance, electrically-passive termination jumper and an insulated, low-impedance conductive cable. The electrically-conductive shield is configured for placement over the pencil-assembly cable to thereby cover and extend coaxially with the pencil-assembly cable. The termination jumper is couplable to and between the return-pad-assembly terminal and ESU, and the conductive cable is coupled to and between the electrically-conductive shield and termination jumper.
