You can extend a circuit to accommodate the addition of a ceiling light and switch. Keep in mind that this process involves three locations—the existing power source, the new light switch box, and the new fixture box located in the ceiling.

1) Position the fixture box between two ceiling joists and cut the hole for its location. Next, cut a hole for the switch box, and make a hole where the wall meets the ceiling. Drill a hole in the top plates. Now, cut an access channel along the baseboard between the switch box location and the power source.

2) Run one cable between the power source and the switch box hole. Next, “fish” a second cable from the switch hole to the access hole, doubling back along the baseboard.

3) “Fish” from the fixture box hole to the access hole via the drilled hole in the top plates. Attach the second cable and pull it through the access hole, the top plates, and out the fixture box hole.