The Square D generator panels allows you to permanently connect a standby power source to specific circuits, such as lighting, heating, refrigerator, freezer, and sump pump. You can easily switch the power supply to branch circuits by turning off the utility main breaker and turning on the main breakers connected to the generator. For added safety, an easy to use rotating interlock bracket allows only one main breaker to be on the "ON" position at the same time. Ideally suited for residential, rural, commercial applications requiring a quick and easy switch over from utility power to standby generator power. Large circuit breaker capacity. Accepts up to 18 standard or 36 QO tandem circuits. Includes two factory installed 30A 3 pole main breakers. Ease of use from our patented rotating interlock bracket design. Manually switch from utility power to stand-by generator power in seconds. Suitable for generators having either bonded or unbonded neutral conductors.