90 Degree Warning

Recently purchased 2 light fixtures. Upon installing, I noticed both fixtures contained warning: Supply wiring must be rated for 90 degrees C or higher. Homes built before 1980's may be rated below 90 degrees.

What does this mean? My home was built in mid 1970's and has copper wiring. I have installed other lights similar to these and don't remember ever seeing a 'warning' (have had no problems). A guy at Lowe's told me if I have copper wiring, I should be OK. Thoughts??
Thanks!

 

The 90 degree c rating applies to the type of insulation used on the wire. Homes built around the time of yours were commonly wired with insulation rated at 60 degrees c. What happens is the insulation if not rated for the higher temperture gets baked to the point were it could crack off. This commonly used to happen here in the Chicago area when they used to use rubber covered insulation in the 40's and 50's and homeowners would put larger lamps then the fixture was rated for.

 

A brand of fixture I put up a few years ago came with high temperature sleeves about 6" long to slide over the existing wire. I haven't seen it since. Seemed like a great idea if legal to get around the problem.

 

Two ways to look at it. One, an issue I have strong reservations about, is basically lawyers writing wiring instructions. Buy a power tool at Sears and see how much of the instruction manual is technical guys telling you how to actually use the tool, and how much of it is NAFTA and lawyers dictating the document. 21 Pages. 7 of them are English. And about one of them are actual useage advice. The other 6 are liability-based "Safety" warnings.

With your light fixture, use higher that recommended bulbs, start a fire and switch to lower wattage to avoid liability before insurance inspectors get there, you could go after the mfr. So lawyers go with 90 degree wire to protect their client from you. Most fixtures do not require really high temp. wire. BUT, and a big but, I don't want to be sued either, and must say that NEC requires you to follow mfr's. recommendations beyone what is req'd by Code. So I am not telling you that you will be OK to blow them off. Take your own meaning from this. But I have personally seen and had to correct aluminum '70s wiring where bulbs clearly exceeding sticker on fixture used where such bulbs caused insulation to crack off exposing bare wire that could easily have caused fire but did not, miraculously. You install fixtures without 90 degree C wiring and next owner is a moron who puts 100 watt bulbs in 60 watt labeled fixture, and now maybe you're sued. Crappy answer, but you should probably see my point. Tough call, legally, but common sense in other ways. Sorry if I muddied the waters, but I won't go on record for saying the mfr. is full of of it and do what you please. Use your best judgement here.

Good luck, Juice