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I’m a novice when it comes to electrical. I bought a new LED ceiling light fixture and found a “Min 90 degree supply conductors” warning after opening the box. I read a bit about it but I still don’t quite understand how I would know if this is an issue in my house or not and whether it’s safe to install. My house was built in 1974 so does that mean I automatically have the wrong wiring to support the new fixture? Would I need to go to my breaker box and look at the wiring?

Thanks in advance.

box 1

box 2

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  • Make/model of lighting fixture?
    – manassehkatz-Moving 2 Codidact
    Commented Dec 26, 2022 at 21:30
  • Aaru Glass Flush Mount - wayfair.com/lighting/pdp/…
    – Dave
    Commented Dec 26, 2022 at 22:04
  • Is the existing cable designated as type "NM" or "NM-B"? I suspect 1974 is NM which I think is only 60°C. I don't know what year the started making NM-B with 90°C wire.
    – NoSparksPlease
    Commented Dec 27, 2022 at 17:21
  • Do you own or rent the house, please? Here in the UK as a mere home owner it might be legal to burn down my own house, but work on tenanted rental property may only be carried out by a qualified electrician.
    – Robbie Goodwin
    Commented Dec 28, 2022 at 15:37

2 Answers 2

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The most common known house wiring (such as Romex and similar) is rated at 90° C for its insulation. Additionally that fixture is spec'd for incandescent bulbs. If LED bulbs are used they will produce less heat. The fixture is UL rated. It should be fine for installation unless you have some odd owner installed wire.

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  • thanks for the help. I just added 2 photos to my original post- are you able to make sense of what I have and if everything looks OK from what you can tell. Thx
    – Dave
    Commented Dec 27, 2022 at 0:59
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    What is important are the wires in the ceiling box that are being attached to the new fixture. Those most likely carry the rating that is necessary. However no one here can give a 100% ok as the chance exists that those wire are substandard. Your concern is understandable, but know in most cases of modern home wiring the wire do meet the standards. There just is not enough evidence for us to see here to give that a stamp of approval.
    – RMDman
    Commented Dec 27, 2022 at 1:30
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Often, mains wiring is labeled to show the temperature rating. The letter code THHN is equivalent to having 90°C printed on the wire. If you cannot find a label on the existing wires (look along a length to find it), you could add another junction box, connect higher-temp rated wire, and then feed that into the existing box for the fixture.

That said, 90° C rating seems to be a rather high requirement; perhaps another fixture, with lesser requirement, would be easier to install.

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    Note that the wires in NM-B cable are also required to meet the 90degC mark (although they're mystery meat otherwise)
    – ThreePhaseEel
    Commented Dec 26, 2022 at 23:39
  • I just added photos- does that help clarify anything? Thx
    – Dave
    Commented Dec 27, 2022 at 0:57
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    Your photos aren't close in enough to read the lettering on the wires. AND, technically (as discussed above) the wire you care about is the end located in the ceiling where you're installing the fixture (but it's probably the same as what we see here.)
    – Glenn Willen
    Commented Dec 27, 2022 at 1:19
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    And a lot times that kind of information is embossed on the cables - not printed - and so would be very hard to show in a photo.
    – SteveSh
    Commented Dec 27, 2022 at 20:42

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