Planning the Circuit
Plan the circuit for the fans. Do not exceed more than 1,440 watts on a 15-amp circuit or 1,920 watts on a 20-amp circuit.
Check the fans to see that their wattages fit within these parameters.
Check the amperage rating on your breaker box to make sure your home power supply can handle the additional circuit. You can determine this by calculating the total number of amps your home draws and comparing it to the rating on your service panel.
Buy cable appropriate for the type of circuit. A 20-amp circuit requires 12-gauge cable, while a 15-amp circuit requires cable no smaller than 14-gauge.
Kill the power to the service panel and add the new circuit by attaching the black (hot) wire to the circuit breaker and the white (neutral) wire to the neutral bus bar. Snap the breaker into place.
Run the cable as straight as possible to the room where you will be installing the fan.
Hanging the Fans
Cut the openings in the wall and ceiling where you will be placing the switch and fans. Cut another, smaller opening directly above the switch where the wall and ceiling meet to make threading the wire from the switch to the fans easier.
The ceiling holes should be about 6 inches in diameter and each should be centered between two ceiling joists.
Attach the switch box to the wall. Switch junction boxes do not need to be attached to wall studs and can be affixed directly to drywall or plastic.
Hang each fan’s brace bar, fastening it to the ceiling joists. Attach a junction box to the bar.
Run the electrical cable from the service panel to the switch box. Connect the black (hot) wire to one of the brass screws on the switch.
Run cable from the switch to the first fan junction box. Attach the black wire from this cable to the empty brass screw on the switch.
Connect the two white wires.
Run cable from the first fan to the second. At the first junction box, attach the black wire coming from the switch to the black wire leading to the first fan and to the black wire leading to the second fan.
At the first junction box, attach the white wires together.
Connect the black and white wires at the second junction box to the fan.
Attach the fans to the brace bar according to the manufacturer’s instructions.