How to Wire a Ceiling Fan With No Existing Source

Determine the proposed location of the ceiling fan. The location should be between a joist. Cut a hole in the ceiling just large enough for the electrical box to fit. The box will be installed from the level above. Most ceiling fan electrical boxes are attached to a metal bar designed to extend to the joist on either side of the electrical box. Both ends of that bar must be bolted to the the joist on either side of the box, which gives the electrical unit added weight bearing capability. Make sure that the box is flush with the ceiling before bolting it down. If it is not, washers may be added between the joist and the bar to raise the electrical box. Install the electrical box and secure it to the stud in the ceiling. Then locate the closest ceiling light fixture and turn off the power to that light fixture at the main power panel.

Run a 12-gauge NM-B electrical cable from the newly installed electrical box to the existing light fixture. Detach the existing light fixture from the ceiling and support it, but do not disconnect the wiring. On the new NM-B cable, strip a 1/2 inch of insulation off of both the white and black wires. In the existing light fixture's electrical box, remove the plastic twist cap off of the two black wires. Run the new NM-B cable into the existing light fixture's electrical box and add the new black wire to the two existing black wires of the light fixture. Place a larger twist cap to hold and join all three black wires. Repeat this process for the white wires to connect them. Push these wires back into the existing light fixture and reattach the light fixture to the ceiling.

Push the other end of the new cable into the electrical box of the new ceiling fan. Strip a 1/2 inch of insulation off of both the white and black wires. Support the ceiling fan close to the electrical box to make handling the wiring easier. Twist the black wire from the electrical box to the black wire from the ceiling fan and add a twist cap. Repeat this process for the white wires and add a twist cap. Push the wires up into the new electrical box. Secure the fan to the electrical box.