Why can't loose fiberglass contact non-IC rated recessed light?

[St. Joseph]

I have loose (blown-in) fiberglass in my attic. If fiberglass is noncombustible, why then is not allowed to contact a non-IC rated recessed light?

 

[g3vlftrevor]

Glass fibre is a very good thermal insulator. The lights need to be able to get rid of waste heat to stop overheating and possible fires.

 

[Don Farrell]

If your light has a "Non IC" listing, it cannot be covered with insulation. It's not the heat on the fiber glass that's the problem. Non IC lights normally have a thermal fuse in them. If the heat internal to the lamp get's high enough the link will open and the light will shut off until it cools down.