An automatic switching interface box for generators in residential dwellings and small commercial applications provides a breaker box transfer switch for generators powering one or more electrical loads. In power blackout situations, the breaker box transfer switch uses a power control relay to keep the load power on, which eliminates the need for a hot generator plug, because the plug in box is not powered. The generator power output cord is plugged onto the male plug of the interface box, or hard wired thereto. If the auxiliary generator had been started and is at rated voltage, the load is immediately and automatically switched from the utility connection to the generator as electrical source. The relay keeps the prongs of the male plug safely unpowered until the generator is attached since the relay coil is powered by the generator output and the plug is connected to the normally open contacts.