We had a light bulb explode in a fixture in our bathroom last night. What might cause this? My son had just finished a very hot shower and the room was very steamy. Also, the fixture is old and one of the other sockets is loose and it is difficult to tighten up the bulbs in it.
If the fixture has a bulb that is exposed as opposed to one encapsulated in a dome, then it may have been the condensation on the glass that did it. The bulb would have to have been really hot and the condensation from the shower developed on the bulb causing the glass to expand/contract at different rates and breaking it. Even glass that is designed for high temp. use can have this happen if a small concentrated heat source is applied. For example, I took a 9 inch Pyrex baking dish that had a bunch of baked on crud, filled it with water and put it on my burner. About 10 minutes or so later I had hundreds of tiny Pyrex shards all over my kitchen.
Solution: open a window or turn on the exhaust fan (if you have one).
P.s. All of this is an educated guess, but I'll bet I'm not too far off. Unless your light all of the sudden got 240 volts. But I doubt it.