An electrical circuit includes a first circuit part and a second circuit part. A first electrical potential is applicable to the first circuit part, wherein a second electrical potential is applicable to the second circuit part. The two circuit parts are galvanically isolated from each other by an insulator, wherein the insulator includes a conducting portion. This conducting portion can be safely sensed by an additional circuitry, to detect if a full or partial contact to the first electrical potential or the second electrical potential has occurred due to a voltage shift or a current flow on the conducting portion, which is itself insulated. This sensing circuitry can incorporate protection elements to clamp voltages and limit currents to prevent destruction of connected circuitries in case of a fail of the insulation.