I recently installed a new lighting fixture in my kitchen. The instructions state in big bold letter " for supply connections use wire rated for at least 90 deg C. Warning: risk of fire most dwellings built before 1985 have supply wire rated 60 deg c. Consult a qualified electrician before installing.". I installed the fixture anyway. My house was built in 1968. I checked some extra wire I had laying around and it doesn't mention a C rating. How big a problem is this or how long will it be before my house burns down? Thanks.