A generator transfer switch (TS) allows normal alternating circuit (AC) line voltage to connect with the utility power, but when there is an AC problem, the switch diverts the electric load to a generator. The law states that you must install a power transfer switch before you connect a generator to a building's electrical wiring system.
Choose a switch that is manual, automatic or a combination of the two. Automatic switches have a control circuit that senses the interruption of utility power and turns on the generator; then it turns the generator off and switches it back to utility power when the AC problem is resolved (see Resources).
Contact the power company to shut off the power. Have the meter removed and make sure there is no power on the meter base unit.
Install the power transfer switch to the left or right of the load center, and place it approximately 18 inches from the middle of the circuit center. Secure the switch to the wall with fasteners that will not harm the material on the wall.
Take the cover off the load center and remove the cable that runs from the meter base unit to the house. Run a cable from the meter base unit to the commercial input on the transfer switch.
Secure the locknut tightly onto the load center, and allow the wires to hang freely. Remove the knockout, run the generator wires that come from the conduit upward through the knockout and hook them to the accessory input on the generator transfer switch.
Find the wire you previously removed from the meter base and run it to the output of the transfer switch. Call the power company to have the utility power turned back on (see Resources).
Make certain you have grounded the generator and neutral unbonded at the generator. Test the power transfer switch to make sure it works.
Don't attempt to install a generator transfer switch unless you have advanced electrical knowledge. Check your local code and contact a licensed electrician. Don't run the generator in the house or garage, and move it about 12 feet away from the house.