A computer system comprising a processor device is configured to identify a charging start of the battery provided in an electric marine vessel, actuate, in response to identifying the charging start of the battery, a switch on a protective earth cable from a disconnected state to a connected state, wherein the PE cable is provided between a PE shore connection point on shore and a PE hull connection point on the vessel, initiate charging of the battery via a charging cable connecting the battery on the vessel to a power supply connection point on the shore, identify a charging end of the battery, and actuate, in response to identifying the charging end of the battery, the switch on the PE cable from the connected state to the disconnected state.