Home>Discussions>ELECTRICAL & LIGHTING>Sealing Ceiling Fan Electrical Box
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MN55
Sealing Ceiling Fan Electrical Box

We recently installed new electrical boxes and hung fans from them. We caulked around the boxes to seal off airflow into the attic. There are several small holes (and one has a medium sized hole) on the boxes. What's the proper way to seal this off to prevent the blown-in insulation from falling through the hole into the box (a fire hazard I presume)? Is caulking them appropriate or just putting a piece of electrical tape over the holes?

Thanks

MLB Construction
Re: Sealing Ceiling Fan Electrical Box

the proper way is to install a cap in the attic over the electric box. the easy way is to make one out of metal duct tape and rigid foam insulation.

i hope you installed the electric boxes that are rated to hold ceiling fans. if you installed old work boxes it would be very wise to change them.

HoustonRemodeler
Re: Sealing Ceiling Fan Electrical Box

If the holes are large enough to allow insulation through, something is wrong. Were extra punch out holes opened that don't have wire through them ?

MN55
Re: Sealing Ceiling Fan Electrical Box

MLB Construction, what sort of cap? The boxes are mostly enclosed on all sides except the side that hangs down to go to the ceiling fan.

HoustonRemodeler, The boxes and accompanying braces are rated for ceiling fans. The holes are not huge, about the size of a screw head and there is a bit of space around the grommet that allows the wire to go in. Just was curious if those posed a hazard for very small pieces of insulation or dust or anything. And if so I should do anything about them. Ill check again, but I also remember a hole that was a bit larger...

Thanks for your responses.

dj1
Re: Sealing Ceiling Fan Electrical Box

I think MLB misunderstood your posting and thought the boxes are not in use.

Anyway, a black electrical tape should be able to take care of those tiny holes.

MN55
Re: Sealing Ceiling Fan Electrical Box

ok thanks dj1. I assume there should be no heat concerns with that or anything?

HoustonRemodeler
Re: Sealing Ceiling Fan Electrical Box

no heat concerns as there is no heat source other than from the attic.

Fencepost
Re: Sealing Ceiling Fan Electrical Box

If the blown-in insulation is fiberglass, there is no short-circuit or fire hazard concern.

Sealing the boxes should be done to block airflow for the purpose of energy efficiency**. Cheap adhesive caulking ($2/tube) works just fine for this.

Insulation can safely come in contact with standard electrical boxes. Only recessed lights that are not rated for direct contact with insulation require an additional box around the fixture for energy efficiency and to prevent insulation contact.

**Regarding energy efficiency: in the summer, it keeps cold air in and warm air out. In the winter it keeps warm air in and cold air out.

MN55
Re: Sealing Ceiling Fan Electrical Box

Thank you for the advice.

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