As far as I know your correct about the residential wiring of the era.
My guess is that the manufacture said 90 c. Which is what the newer residential wire is rated for, I believe. You could always pig tail a piece of thhn or thwn to the home wiring and then connect to the fixture.
I purchased a energy efficient ceiling fixture to replace a kitchen light. (It is not recessed). The directions warn that it should not be connected to house wire not capable of withstanding x degrees Celsius. (I think x is 70 or 90). Since my house was built in the 1960s, I don't have any idea how hot max the wire is designed to get, but IIRC most wire of that era was designed for 60 C.
So what is the proper way to wire a new fixture? I'm surprised the wire temperature max rating is such an issue, the enegy efficient florescent lighting seems to be much cooler than incandescent.
Thanks!
The light itself is cooler, but florescent lights have a "ballast" which can get to be quite hot. (At least with commercial fixtures.)
Heat travels up, also heat can get trapped with insulation, in the metal box holding the electrical wires, etc.
I've seen insulation from old wires just crumble when I removed a wall fixture in a bathroom. And that was not even a ceiling fixture. Some of the insulation had fallen off by itself. Note that this fixture was part of a metal medicine cabinet, so could have been a shock hazard as there was no grounding!
The heat from the fixture wrecked the insulation on the old wiring.
I would replace the wiring whether it needs it or not, since it may have been damaged by the previous fixture. The new stuff is *so* much safer than the old (grounding, high heat insulation, etc.)!
I think it's an easy method for the manufacturer to exempt themselves from liability in case of fire. Most houses don't have 90 degree wire and I doubt most people are going to rewire the outlet box just to accommodate fixtures with that listing. Having said that, there are however fixtures made that do generate a lot of heat on the outlet box they are attached to and the wire supplying those fixtures should be of 90 degree rating
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I've run acoss the same thing - you move the wire and the insulation still remianing cracks off. Old circline flourescent fixtures could cause this.
The solution? Get a fixture that is rated for 60°C supply wiring. It is common for fixtures to have insulation built into the top to limit heat problems. I'm not impressed with the fixture manufacturer. Seems obvious a lot of these will be installed with 60°C wiring.
Bud--
I can not understand how a florescent should get that hot, You might call the manufacturer and question them in this matter. But if thats what is required, see if you can get to the cable from your attic or something. Turn off the power, remove the cable, put a junction box on the next rafter and run a piece of approved wire to the old ceiling box.
One note, on all the old and new enclosed indecesant bulb fixtures, I always drill a few holes in the base, (about 1/8 to 1/4 inch) near the ceiling. That allows much of the trapped heat to escape. It's not all that noticable and saves the wires.
Mark
No you can't. The lower rated 60C rated conductors need to be far enough away to be unaffected by the heat the fixture gives off. If the space above is accessible you move the old cables into a Jbox and run a cable from that Jbox to the fixture box. If the old cables are not relocated the heat from the fixture will cook the insulation right off the wires and they will fault out. Because the process is gradual it has a higher likelihood of arcing faults that can kindle a fire.
-- Tom Horne
"This alternating current stuff is just a fad. It is much too dangerous for general use." Thomas Alva Edison
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