Plastic electric boxes and ceiling fans?

[Apropos]

I wish to hang a clg fan where there's an existing plastic box.

I believe the plastic box is supported by a metal between-stud bracket. I plan to reinforce the box by putting a 2x4 above the box and using lag bolts w/washers thru the box to support it.

My question would be the THREADS of the box. I'm sure the box itself, as it will be supported, would well stand the force of the fan; however there's a big question if the THREADS would have any problem.

One thing about the plastic threads is that you have a large number of them (sticking the screw up to 1" into threads) as opposed to the steel, which has only a small number of threads. Anyone have experience with this?

If I need to get the box off, how best to do that? Would I *HAVE* to do it in the attic? It's VERY hard to get in there and I want to use the existing hanger, only REINFORCING the box with the new wood. I don't see any internal screws which hang the fixture :(

[RBM]

If this box doesn't have internal screws to attach it to the bar above, it's not a bar box. It would likely be a side bracket box, nailed to the side of a ceiling beam. The best thing to do is completely remove the box and install a fan support box. There are ones like Westinghouse 01100 which will install from below and bridge the beams. If you can get above the box to install support wood, you should be able to easily remove the existing box. If you did choose to use the existing box with wood support above it, Don't support the fan from the plastic threads, but run long lags through the box and into the support wood above

[scott21230]

I would not attach a ceiling fan to a plastic box.

[trader4]

I've never seen a plastic box designed to hold a fan, nor would I use one. Find it hard to believe they would make one with a metal bar and plastic box. Seems more likely this was rigged on the fly.

[Steve Barker]

There are plenty of plastic boxes rated for hanging fans on. Also with the reinforcement you plan to do, it'll be fine. After all fans don't weigh anything like they used to. I've hung dozens on plastic boxes that are supported with a two by four above them and some extra screws shot through the top of them. It's not a jet engine we're hanging here.

?action=productDetail&productId=44006-223-B720-SHK&lpage=noneHere's the side nail on unit

[John Grabowski]

Here's the side nail on unit

The two Carlon boxes mentioned above from Lowes are not listed for ceiling fans in the Carlon catalog. The other two plastic boxes are not actually used for fan support. The box manufacturer provides long wood screws for the fan bracket to be screwed through the box directly to the wood support behind it. These are usually used during new construction

Carlon does make a plastic ceiling fan rated box #BH525L rated for 35 lbs and used during new construction. If there is access from above I suppose it could be installed in an existing structure.

I usually just remove the existing box and install a retrofit fan brace and box. It keeps me out of the attic and the fan support is solid. In condo's I don't have the luxury of an attic. I use my BX cutter's to cut through the existing brace and after a couple of twists and bends the two pieces come out.

[sym]

if its not a fan rated box i wouldnt use it. if your already going to put in the 2x4 just remove exsisting box put 2x4 across center of hole and install a fan master 2000box or similar style from below it will look like it was always there when your done.

[Just Joshin]

Is the box listed for ceiling fans?

tom @