Wiring is disclosed herein that is configured to supply IRE ablation signals through a catheter body and is resistant against dielectric breakdown, arcing, and noise during ablation. The wiring includes a highly conductive core, a conductive cover surrounding the core that has lower electrical and/or thermal conductivity than the core, and an insulative jacket surrounding the conductive cover. A catheter including such wiring may be suitable for supplying electrical signals to tissue to perform IRE ablation. In some examples, such a catheter can also be suitable for reversible electroporation and/or RF ablation.