Patent ID: 7336457
Filing Date: 2008-02-26
Classification: H01H,H02H

Abstract:
1. An end-of-life status alarm indicator for ground fault circuit interrupter (GFCI) apparatus comprising: a primary contact relay for opening and closing primary power contacts, wherein said power contacts are respectively located in first and second conductive paths and allow current to be supplied to the load side of said GFCI apparatus; a control circuit for detecting the occurrence of an imbalance in the current flow through first and second conductive paths that is indicative of a ground fault condition at an AC load connected to said GFCI apparatus and generating an imbalance occurrence signal; an imbalance response circuit for deenergizing said primary contact relay in response to said imbalance occurrence signal from said control circuit, wherein said primary contact relay when deenergized allows the primary power contacts of the GFCI apparatus to open; an end-of-life (EOL) status alarm indicator circuit having an indicator for providing an indication when a current flow imbalance occurs and said primary contacts fail to open when said primary contact relay is deenergized, said EOL status alarm indicator circuit being configured to receive power from said load side to energize said indicator when the primary contacts are closed and said primary contact relay of the GFCI apparatus is deenergized; and a switching circuit comprising semiconductor devices for shorting a circuit path necessary for said EOL status alarm indicator circuit to provide said indication of said failure of said primary power contacts to open, and controllably opening the short circuit to allow said EOL status alarm indicator circuit to use said circuit path to receive power from said load side and energize said indicator to provide said indication.