Installing a ceiling electrical box lets you add a light fixture to a room. If you want to install a ceiling fan then you will need to get a box rated to hold the weight of a ceiling fan or you will want to add some additional bracing to hold the ceiling fan. Installing the box is easily done but you must be careful anytime you are working with electrical wiring.
Step 1 - Check Building Codes
Inquire with the city to see if any building codes apply to the installation. Most cities have guidelines for the installation of electrical wiring and you want to be sure you are complying with the guidelines that they set up.
Step 2 - Prepare the Area
Put on eye protection and wear shoes that will keep your feet steady on a ladder. Place your ladder securely. Put down a drop cloth to catch any falling debris. Be sure to turn off the dedicated circuit breaker and test to make sure the line is dead.
Step 3 - Position the Box
Decide where you want to place the electrical box. The obvious factor is where you want the light or fan to be positioned, often in the center of the room. However, you should also consider what kind of support the box will be fastened to, where the electrical wiring is already present, and how the wires will be connected to a switch or the main breaker box. Considering all these factors in advance will make the process quicker.
Step 4 - Run the Wires to the Box
Run the unconnected electrical wires from a switch or the main breaker box to the location where the box will be mounted. Push out one of the prepared openings in the outlet box for the electrical wiring. Put the cable through the hole into the box and pull through the cable.
Step 5 - Attach the Box
Put your outlet box against the ceiling rafter or a support bracket, and attach it by nailing it or screwing it through the predrilled holes. Consider the thickness of the drywall, making sure to place the box where it is or will be flush with the ceiling drywall. If your ceiling is already covered with drywall, you may need to go up into the attic where you have access to the rafters so that you can secure the box directly to the rafter. Cut a hole in the drywall below the box to run the wires and other connections to the light or fan.
Step 6 - Wire the Outlet Box
Wire the outlet electrical wires to the electrical cable by matching up up the colors of the wires and connect together by stripping the wires if needed. Twist the matching wires together and cover each bare connection with a wire nut to prevent electrical shorts. The wires should fit tucked into the box.