An improved ground-fault circuit interrupter (GFCI) device has a moveable lock plate controlled by a relay to block a hole under the reset guiding member to prevent reset of the device. The moveable lock plate blocks the hole and prevents reset when the relay is not energized, and expose the hole to...http://www.google.de/patents/US7701680?utm_source=gb-gplus-sharePatent US7701680 - Ground-fault circuit interrupter
