Patent ID: 6657837
Filing Date: 2003-12-02
Classification: H02H

Abstract:
A method of providing fault lockout protection in a circuit breaker, the circuit breaker having a plurality of contacts forming part of an electrical distribution circuit, the contacts being separable to isolate a load side of the electrical distribution from a line side of the electrical distribution circuit, the line side having a line voltage, the method comprising:providing a first test voltage at a first frequency to the load side of the electrical distribution circuit to induce a first test current in the load side of electrical distribution circuit, the first test voltage being less than the line voltage; sensing the first test current to provide a first sensed signal indicative of an electrical characteristic of the first test current; detecting a fault condition on the load side of the electrical distribution circuit in response to the first sensed signal; preventing closure of the separable circuit breaker contacts upon detection of a fault condition on the load side of the electrical distribution circuit; providing a second test voltage at a second frequency to the load side of the distribution circuit to induce a second test current in the load side of the distribution circuit, the second test voltage being less than the line voltage; and sensing the second test current on the load side of the electrical distribution circuit to provide a second sensed signal indicative of the electrical characteristic of the second test current, said detecting the fault condition on the load side of the electrical distribution circuit is in response to response to said first and second sensed signals.