On PKP the devices located close to the electrified track are electrically connected to the rail to ensure fast cut-off power when close-circuits occur. The traditional solution was to connect the overhead wires’ masts individually to the rail instead of having them earthed (individual grounding). The changeable short-circuit protection system with group grounding in the open configuration is a new solution that has been run by Polish State Railways since 1996. The system has been installed on 500km of the double track line to complete tests as well as collect the results and evaluations of those tests. Group grounding operating in an open configuration is the integral element of the new changeable short-circuit protection system.