Will an 08 Prius brake carry electricity?

I am installing a brake pedal on the passenger side for use in Driver Ed. On the driver side, I am have installed a pulley attached to a 3inch x 3inch metal base. This base is attached to the metal floor with 3, 1/4 inch bolts. A steel 1/4 inch cable runs from the passenger side brake pedal to the pulley and attaches to the driver side main brake pedal. I have removed the rubber cover on the driver side main brake pedal and drilled 2 holes in the medal foot pedal. I will attach the cable to the main brake using these 2, 1/4 inch holes. Will this configuration generate an electrical hazard to me while driving or an electrical problem in any way with the Prius?