OVER VOLTAGE PROTECTION CIRCUIT FOR GFCI DEVICE

摘要

An over voltage protection device for a GFCI having a voltage divider network connected across the line terminals of the GFCI, and an over voltage detecting diode connected between the voltage divider network and a gate terminal of an SCR. The voltage divider and diode cause a signal to be fed to the gate terminal of the SCR to trip the GFCI when an over voltage condition exists at the line terminals. The voltage divider is adjustable, with the sensitivity of the over voltage protection varying in accordance with adjustment of the potential from the voltage divider. In an embodiment of the invention, the circuit includes an indicator, such as a photodiode, which indicates the occurrence of an over voltage condition. In addition, a blocking diode is connected between the gate terminal of the SCR and a triggering terminal of an integrated circuit of the GFCI where the over voltage detecting diode conducts current to the gate terminal when an over voltage condition occurs, and the blocking diode conducts current to the gate terminal of the SCR when a ground-fault condition occurs.