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  1. #1
    Join Date
    Nov 2007
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    132

    Default "90 degree C supply conductor minimum.

    Is there a danger to install this light with this kind of warning on package ( "90 degree C supply conductor minimum)? What does this mean? Thanks for responding

  2. #2
    Join Date
    May 2008
    Location
    Pacific Northwet
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    1,643

    Default Re: "90 degree C supply conductor minimum.

    It means that the incoming supply wires must be rated for 90C (194F). If the wire was installed around 1985 or later, don't worry about it.

    If the wire is older, it *might* be rated for 60C or less. This rating applies to the insulation on the wires; above the rated temperature the insulation can begin to degrade. The wires may be heated not from load, but from the heat from the light bulbs. If you install larger incandescent bulbs than the labeling indicates, you can overheat the wires.

    (By the way, the watt rating is actual wattage. For example, if it says 60 watts, that's 60 watts incandescent. A "60 watt equivalent" CFL is only 13 actual watts -- you could safely install a "100 watt equivalent" CFL if you wanted to.)

    If the insulation on the wires at all seems brittle, it has gotten too hot in the past and may indicate a dangerous situation.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

  3. #3
    Join Date
    Nov 2007
    Posts
    132

    Default Re: "90 degree C supply conductor minimum.

    Thanks for this information. It is very helpful. I need to install a motion detector and there are 2 ground wires coming from the 2 different light bulbs. Are they attached to grounding screw in the box or is it attached to grounding
    screw in the fixture?
    Thanks for helping.

  4. #4
    Join Date
    May 2008
    Location
    Pacific Northwet
    Posts
    1,643

    Default Re: "90 degree C supply conductor minimum.

    All ground wires should be connected together with a wire nut. You'll also need short jumpers from any ground screws to this same connection. Yes, this can result in a LOT of wires in one wire nut; if you don't have a big enough wire nut, you can use two wire nuts, jumpering between them. Or use a crimp-on sleeve connector.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

  5. #5
    Join Date
    Nov 2007
    Posts
    132

    Default Re: "90 degree C supply conductor minimum.

    Hi again,
    I would like to know if the electrical box is grounded, what do I do with copper wires coming from light fixture?
    With box grounded I believe it has protection I need? Also the light fixture requires 2-150 watt halogen lights.
    Could it overheat wires as you have explained?
    Thanks

  6. #6
    Join Date
    May 2008
    Location
    Pacific Northwet
    Posts
    1,643

    Default Re: "90 degree C supply conductor minimum.

    If the box is grounded (as it would likely be if your wiring is in conduit), you can attach a jumper wire to a screw in the back of the box. Many boxes have a hole tapped for a #10-32 machine screw for this purpose. Connect that jumper wire to the wire from the fixture.

    If the fixture specifies 150W halogen lamps, then it should be safe.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

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