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?
Using foam in a can, like Great Stuff http://www.homedepot.com/p/GREAT-STUFF-Big-Gap-Filler-Insulating-Foam-Sealant-16-oz-248314/100029171 can be used to fill in gaps to help prevent air leaks.