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Ceiling Fan Junction Box

I recently took down a light fixture in the guest room with the intent of installing a ceiling fan. My home is a 90+ year old rowhouse and does not have an attic, so I can't view from below. What I am seeing is the metal j-box attached directly to one of the main roof joists. It appears to have two bolts and one screw attaching j-box to joist. My question, is this enough to support a fan? The box seems very solid, no movement at all, but all the attachment points are on one side of the box.

I will try to attach pictures later, they don't seem to be working now.

Thanks everyone.

A. Spruce
Re: Ceiling Fan Junction Box

You will have to post the images to an image hosting site, then link them here.

You need to install a fan rated box. Just because a box has a metal clip on the side, doesn't mean that the box itself is capable of supporting the fan. Most fan boxes are metal, or have metal incorporated into their structure to support the fan. The thing with fans is that you're not just carrying their weight, which can be substantial, you are also introducing vibration and movement, which can "work harden" plastic and cause failure.

I'm guessing that you've got brown electrical boxes, which is Bakolite, and incapable of supporting a fan.

Re: Ceiling Fan Junction Box

Thanks for the response. Box is all metal, not plastic.

Re: Ceiling Fan Junction Box

I like to attach a metal box to a blocking (I use two hex screws) that I run from joist to joist - but I need an attic access to do that.

With no attic, you can use a metal hanger made for fans. It goes into the hole in the ceiling, then can be expanded until it's snug between the joists. The junction box that you have now will service the electrical connections only, not to carry the weight of the fan, because the fan will be mounted on this metal hanger.

Not sure? visit a lighting and fan store for details.

Re: Ceiling Fan Junction Box

You can drill holes through the metal box in order to use long screws to attach the fan bracket directly into the framing member. The fan bracket is not required to be attached to the j-box if it is attached to the structure.

Re: Ceiling Fan Junction Box

Keep in mind is not just about the box being attached to the structure but also how many threads are holding the fan to the box. A regular J box does not have sufficient holding threads to be fan rated.

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