Light fixtures with 60 degree conductors

[suemarkp]

I agree that legally you can't because of the labeling. But doesn't the temp rating have to consider the heating due to amp heating in the wires? How can 90C wire be safe if the ambient temp is 89C (it then can't take a full 20A through it because that will add more heat)? If it can take the full 20A, isn't it going to be cooler when the current in the wire is less? I would think 75C rated would be safe if you limit the current in the wires (dead ended light fixtures).

From a labeling point of view, they have no idea how much current could be going through those wires (except the maximum allowed) and need to assume worst case for the label.

 

[macmikeman]

Less than a week ago I hooked up a ceiling fixture that had a base up against the ceiling, a stem that was about 9 inches long, and then the lampholder and glassware down at the lowest part. It accepts 2 60 w type a lamps. I wired it to a run of brand new romex, but I still did the hand touch heat test of the top cap just out of curiosity cause it had the 90 deg label. Not hot. My first guess is that the UL sticker doesn't go on unless that label is going to get put onto the fixture, needed or not.

 

[infinity]

Less than a week ago I hooked up a ceiling fixture that had a base up against the ceiling, a stem that was about 9 inches long, and then the lampholder and glassware down at the lowest part. It accepts 2 60 w type a lamps. I wired it to a run of brand new romex, but I still did the hand touch heat test of the top cap just out of curiosity cause it had the 90 deg label. Not hot. My first guess is that the UL sticker doesn't go on unless that label is going to get put onto the fixture, needed or not.

IMO many of those stickers are just an insurance policy for the fixture manufacturer. I've seen them on fixtures that could never even get the JB conductors warm let alone damage them.

 

[flashlight]

If, after considering all the factors (capacity of junction box, design of luminaire, whether box is terminal or has other loads passing through), you decide to install the fixture, perhaps using shrink-wrap as some have suggested, you can always install fixture with cf lamp, which runs much cooler. I always urge customers to use cfs wherever possible. There is much variety in color temperature these days. If dimming is an issue, the newest generation of dimmable ones seem to perform well. The energy savings are well known. In my 30 unit coop building, we saved over $ 2,000 per year on our electrical bill when we switched over.
However, I will point out that this is not a solution to the problem, since even if the customer is on board with cfs, the person she sells the house to may want to use incandescent bulbs beyond the rating of the fixture.

 

[Pierre C Belarge]

If the fixture is listed to be installed with 90C conductors, you will still be required to follow the listing regardless of the lamps installed.

Shrink tube is not a good fix. One of the worst portions of the conductor receiving damage is the portion where the fitting is. The shrink wrap does not protect that portion of the conductor.

The 90C rated fixtures if installed properly will take more work/cost than just using the existing conductors. Legally there is no way to use the 60C conductors in the box.

 

[guschash]

410.21 (2008 workbook) says "conductors in outlet boxes shall not be subjected to temperatures greater than that for which the conductores are rated.