I just bought a flush mount light fixture to replace the old one on the foyer ceiling. There is a warning label on the fixture that reads "For supply connections use wire rated for at least 90 degrees C. Most dwellings built before 1985 have supply wire rated 60 degrees C."

Our house was built in 1950. The solid, copper wires coming from the ceiling seem heavier than the braided aluminum-looking wires on the new fixture. Should I be worried about this?

What are these rating referring to? Are they the temperatures over which the insulation on the wires will burn? Is the warning really meant to pertain to houses that have cheap aluminum wiring?

Thanks! I installed a Hampton Bays light fixture from Home Depot with no problem last week. This one came from more of a pro lighting center.

The temperature ratings are for the insulation, not the wire itself. All the insulation eventually gets hard and brittle, some more so than others, and the warmer the faster. It can be formulated to take heat better. Some light fixtures generate more heat, and some dissipate it better. So the fixture you have will cook the life out of your old wiring.