Conductive Electric Road Systems (ERS) appear as a promising solution for the electrification of transportation, particularly for heavy vehicles and long-distance trips but also for light vehicles. Significant research efforts are currently devoted to the development of conductive ERS systems, with up to four pilot test sites with different technologies in operation only in Sweden. With the help of electric models and experimental measurements on a pilot test track, this article assesses the potential safety challenges associated with one aspect of this technology: the absence of a reliable protective earth connection while the vehicle is connected to the ERS power supply. The results highlight the importance of monitoring the chassis potential at all times and the need of an active safety mechanism to disconnect the vehicle from the ERS supply if a severe fault occurs.