QO generator panels are for the manual transfer from utility to generator power. QO generator panels are for back-up power applications. This sub-panel connects directly to the main load center and provides four single pole spaces that will accommodate up to eight circuits dedicated for back-up power. This QO generator panel uses two factory installed, two pole QO circuit breakers. One is fed by the utility, while the second circuit breaker is back-fed to the back-up power source, such as a generator. Power source switching is easy. Simply turn the main power breaker to the "OFF" position and then turn the generator fed breaker to the "ON" position. A factory installed mechanical interlock prevents both main breakers being in the "ON" position at the same time. This generator circuit breaker interlock kit is for use on "S2" NEMA 3R QO generator load centers. It is used to interlock a QOM2 two pole main circuit breaker of the load center (150A to 225A) with a QO two pole (15A to 125A) branch circuit breaker. This interlock kit is packaged in clam shell.