I have personally seen incandescent and CFL bulbs above diffuser panels in suspended ceiling setups (even more bizarre than a fluorescent shoplight mounted above diffusers mimicking a fluorescent troffer), mercury vapor recessed can lights inside a home, and a restaurant using real antique 100 year old radial wave streetlights (now repurposed as overhead table lighting).

Let's hear your intakes!

In a cold region, a fluorescent fixture with a heater wire wrapped around the tube, to warm it up doing the startup. But it was done in a crude manner, where it was all manual, even the tube was started with a switch instead of a normal starter.


I also saw an HPS lamp used indoors without any protection. The 250w bare bulb was hanging at head height without any cover.

For me, it was when I was exploring the World Theater in Cedar Rapids, IA years ago. The stage had an arch with dozens of carbon filament bulbs in it, all of which I'm guessing dated back to 1915 when it opened. From what I read, it was only used for live performances for a year before switching to movies, and the bulbs were basically abandoned in place. When I visited, it had been turned into a nightclub and the stage area was closed off. I'm not sure if the nightclub (or even the theater) are still there, but at the time everything back there was preserved exactly as it was nearly a century ago.