An arrangement related to subsea electric power distributing AC-system and adapted for a subsea application. The arrangement is enclosed in a watertight casing. The casing exposes a main power input connection, adapted for watertight co-ordination with a first subsea cable and a main power output connection, adapted for a watertight co-ordination with a second subsea cable. The second subsea cable is adapted for a power supply to an AC-current and AC-voltage adapted device. The arrangement includes interconnected: a voltage regulator connected to the first cable, and a NO-load switching unit connected to the second cable, and a control unit. The control unit is adapted, in a first operative mode, to regulate the output AC-voltage from the voltage regulator towards and to zero, or at least almost to zero, and in a second subsequent operative mode, to bring the NO-load switching unit from an ON-position to an OFF-position or vice versa.