We installed another ceiling fan for a client in Duluth, Georgia. This client had tried installing it themselves at first, but realized the electrical box was not sufficient for the new fan. That’s when they contacted me. I talked to them about why fans need a properly rated heavy duty electrical box, not the builder grade light fixture box that was currently there. So, we changed that out too.
Why Are Ceiling Fan Rated Electrical Boxes the Right Choice?
Ceiling fan electrical boxes that are UL-listed for mounting you fan, will say on the box: “For Use With Ceiling Fans.” It's not recommended that you use standard boxes for installing them. Having a UL-listed electrical box for your fan means it's built to work with the force that comes from a rotating fan.
More Reasons to Use Ceiling Fan Rated Electrical Boxes:
Can hold up to 70 pound fans.
Come in different sizes and and shapes: including a 1/2-inch-deep "pancake" type and a standard 2-1/8 inch deep box.
Are usually round but can be octagonal
Cost more that standard electrical boxes
Can be mounted directly (with four screws) to a ceiling joist or wood blocking, or they can attach to adjustable braces spanning between ceiling joists.