Abstract: An interlock system is for a bypass transfer switch including first, second, third and fourth circuit breakers. First, second, third and fourth interlock assemblies each include a mounting bracket coupled on or proximate to a corresponding one of the circuit breakers, a transmitting member disposed on the mounting bracket and coupled to the poleshaft of the operating mechanism of the corresponding one of the circuit breakers, and a receiving mechanism disposed on the mounting bracket and structured to engage and actuate the circuit breaker trip lever in response to a trip condition. The transmitting member and receiving mechanism each include primary and secondary connections. A plurality of linkages are adapted to interconnect the connections among the circuit breakers in order to provide a predetermined automatic bypass interlock mechanism, without requiring a separate manual locking device.