Located within a GFCI is a movable contact bearing arm which cooperates with at least one fixed contact. When the movable arm is moved up to allow the at least one contact on the arm to close with at least one fixed contact, the GFCI is in a conducting state and current flows from a source of electricity...http://www.google.de/patents/US7227435?utm_source=gb-gplus-sharePatent US7227435 - GFCI without bridge contacts and having means for automatically blocking a face opening of a protected receptacle when tripped
