A method comprising transferring, via a local interface, electrical power between a central interface and a local electrical system, wherein the transferring of electrical power comprises sending electrical current back and forth via local power lines (41,42) between the local interface and the central interface, wherein the central interface is electrically connected to transfer the electrical power to and/or from an electrical grid via a central interface switch, wherein the central interface switch comprises a residual-current circuit breaker for severing the electrical connection to the electrical grid when an imbalance occurs in the electrical current being sent back and forth via the local power lines (41,42); monitoring, by a controller of the local interface, a status of the local electrical system; and responsive to detecting a fault condition in the monitored status of the local electrical system, activating a leakage circuit of the local interface to generate a current imbalance on the local power lines (41,42) for causing the central interface to sever the local electrical system from the electrical grid by triggering of the residual-current circuit breaker of the central switch characterized in that the local interface comprises a local interface switch configured to selectively disconnect the local electrical system from the local power lines (41,42), wherein responsive to detecting the fault condition in the monitored status of the local electrical system, as a primary means of protection, the controller initially sends a control signal to the local interface switch causing the local interface to sever the local electrical system from the electrical grid; as a secondary means of protection, the controller, subsequently and only responsive to determining that the local interface switch is not operable to disconnect the electrical power, activates the leakage circuit to generate the current imbalance on the local power lines (41,42) causing the central interface to sever the local electrical system from the electrical grid. transferring, via a local interface, electrical power between a central interface and a local electrical system, wherein the transferring of electrical power comprises sending electrical current back and forth via local power lines (41,42) between the local interface and the central interface, wherein the central interface is electrically connected to transfer the electrical power to and/or from an electrical grid via a central interface switch, wherein the central interface switch comprises a residual-current circuit breaker for severing the electrical connection to the electrical grid when an imbalance occurs in the electrical current being sent back and forth via the local power lines (41,42); monitoring, by a controller of the local interface, a status of the local electrical system; and responsive to detecting a fault condition in the monitored status of the local electrical system, activating a leakage circuit of the local interface to generate a current imbalance on the local power lines (41,42) for causing the central interface to sever the local electrical system from the electrical grid by triggering of the residual-current circuit breaker of the central switch characterized in that the local interface comprises a local interface switch configured to selectively disconnect the local electrical system from the local power lines (41,42), wherein responsive to detecting the fault condition in the monitored status of the local electrical system, as a primary means of protection, the controller initially sends a control signal to the local interface switch causing the local interface to sever the local electrical system from the electrical grid; as a secondary means of protection, the controller, subsequently and only responsive to determining that the local interface switch is not operable to disconnect the electrical power, activates the leakage circuit to generate the current imbalance on the local power lines (41,42) causing the central interface to sever the local electrical system from the electrical grid.