How to Retrofit a Ceiling Fan Electrical Box
Use a fan-rated outlet box that will support the fan's weight and its motion. Look for the label to be sure.
Apr 28, 2009
Before installing a ceiling fan, make sure that you follow the portion of the electrical code that requires that you use a fan-rated outlet box that will support the extra weight and the motion associated with a fan. A fan-rated box will be labeled as such inside and typically can support up to 70 lb.
Low profile
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| A 1⁄2-in.-deep pancake box is meant to be screwed to a joist or block. It’s used if only one cable is coming into the box. | ||
Deeper profile
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| A 2-1⁄4-in.-deep box can be attached to blocking between joists and is roomy enough to handle more than one cable. It is also available in a saddle-mount configuration. | ||
No blocking, no problem
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| Paired with a deep box, this hanger is meant to span between two joists and takes the place of wooden blocking. | ||
| Read the complete article… Retrofitting a Ceiling Fan With common-sense wiring and the right hardware, you can replace an existing light fixture with a breeze in almost any room in the house by Clifford A. Popejoy  |
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Perfect article for me — I'm a ceiling fan in the bedroom that keeps me awake all night because it is moving erratically, and frankly I'm scared them drop down on me at any moment. Obviously when it was installed by builder didn't think to attach it properly to the joists, so that something I'll do on my own. Any tips on removal of the old box?