In the event of a power outage the ideal emergency solution for a home or business is an automatic standby generator. These systems automatically transfer the power load to the generator when an outage occurs.
If you plan to use a portable generator to back up your home or business it should be used in conjunction with a manual transfer system which consists of a manual transfer switch, power inlet box, and power cord.
The switch is connected to the main electrical panel so that only the circuits to be powered by the generator are active during an outage. The power inlet box is mounted outside the home or business. It is hardwired to the transfer switch and connected to the generator by a power cord.
When the lights go out, you first shut off the power from the utility at the manual transfer switch, then start the generator to energize the selected circuits wired to it. This will prevent your generator from backfeeding power into utility lines and possibly injuring the repair crews.