Electrical Wiring - How to safely support a ceiling fan45-90 minutes
Subjects in this article are covered by the National Electric Code - NEC 2005 sections 314.23, 314.27(D) and 422.18(a)
Whenever you are replacing an existing light fixture with a ceiling fan it is safe to assume that the work box that the light was installed on will not be sufficient in itself to safely and legally support a ceiling fan. Fortunately, there are several ways to remedy the situation. The National Electric Code article 314.27(D) states that a box cannot be the sole means of support for a ceiling fan unless it is listed and designated by the manufacturer as such.
If you choose a fan with a large diameter base, then you can support the fan by fastening it directly to the ceiling joist that usually adjoins the box, thus not relying on the box to support the fan at all. You can't do this unless the base is at least 6 1/2" in diameter more or less, because the screws that you use to mount it need to go through the fan bracket as near as possible to the center line, and you want the finished installation to cover the work box. This is very similar to what happens with a fan rated plastic "saddle" box.
Supporting the fan independent of the box as described above should satisfy the requirements of the NEC, however local jurisdictions are not required to adopt the code as is, and in some areas you may be required to always use a metal fan rated box. In this case, there are several products available (from home improvement centers especially) that allow you to fairly easily install a fan rated box and bracket through the existing hole that is left after removing the existing work box. Personally, I would probably rather use one of these devices than to work in the attic even if the area is accessible. However, if you are younger, and more limber than I, then climbing into the attic to change out the work box may be a viable option.
Disclaimer: I am not a codes official. I am also not an expert on electrical wiring. This web page is strictly for entertainment purposes. This stuff could be completely wrong, and you should assume that it is. If you choose to do wiring work of any kind then you and you alone are responsible for learning what the code requires, and applying the code to your work. NoJolt and it's employees shall not be held responsible for any inaccuracy of the following content, nor shall we be held liable for any loss of life, limb, or assets caused by the application of this information. If you are going to do electrical wiring, you should educate yourself about the code. If you spot anything in this that you think is incorrect, please contact me at mailto:info@NoJolt.org
How To Do it!
What you will need:
1) Ceiling fan
2) #2 Phillips screw driver
3) Medium slot screwdriver
4) Wire stripper
6) lineman's pliers
7) Wirenuts of the appropriate size (usually red and yellow will cover most needs)
8) A step ladder tall enough to reach your cieling (for 8' ceilings a 6' step ladder is called for)You might also need
A very large slot screw driver
Short pieces (3-4 inches) of black and white copper house wire
A cordless drill and appropriate screwdriver bits would be very useful
If you choose to install a retrofit fan box/bracket combo from below the ceiling then here is the procedure:
1) Wear Eye protection, because you will have debris falling in your face. You might want to put down a drop cloth as well.
2) Turn off the electricity to the circuit.
3) Remove the existing fixture.
4) If there is more than one cable coming into the box, then mark the wires, and draw a diagram in such a way that you are absolutely certain that you can remake the connections exactly as they are after you take them all apart. Taking a few pictures can also be helpful.
5) Take apart all of the connected wires.
6) Remove the existing ceiling box. If it is made of plastic, then you can use a hammer and large slot screwdriver, and a pair of tin snips to break/cut it into pieces, and get it out one chunk at a time. Be careful not to damage the drywall, or wires.
7) If you are removing a non-fan rated metal box, then you can use a hammer and large screwdriver to pound the box straight up until an opening appears between the box and the ceiling joist, then you can pry the box off using the screwdriver as a pry bar. And, yes I know that your shop teacher told you not to use a screwdriver as either a chisel or a pry bar, but I don't know of a better tool for this purpose than a fargin' huge screw driver. Work the wires out of the box once you have the box free.
8) Install the new box and brace as per the manufacturers instructions, but don't forget to clamp the cables into the new box before you install it.
9) It might be possible to connect the wire to the fan motor to full time power so that it does not go on and off along with the light (this is preferable for most people). If there was a white wire and a black wire (or several white wires and a black wire) connected together in your light box then that is where you want to connect the wire for the fan motor, so when you make up the wires add a pigtail to that connection.
10) Other than the exception in 9) Remake the wire connections as they were before.
11) Install your ceiling fan as per the instructions that come with it.