we recently bought 3 light fixtures to install. Nothing fancy. 2 bulbbs, 60 watt max each, low profile. The fixture had a warning saying to consult a qualified electrician because the supply wires should be rated 90 degree celcuis max and most housees built before 1985 are rated for 60 degree max. Our house was built in the 1950s. I think that much of the electrical in the house was updated by a previous owner. I plan on using CFL bulbs. I asked 2 electricians I know and they said not to worry about it.