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    Parking lot lighting

    We are lighting a parking lot with low-voltage fixtures. 12-volt power with 40-watt LED flood lights pushing 4,000 lumens. I understand that the requirement for footcandle measurement is quite low AND we would need to be concerned with the ratios. What is the best resource for this information without purchasing the 2017 NEC book?

    #2
    The NEC has nothing to do with what you are asking.

    -Hal

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      #3
      Lighting recommendations are set by the IES. They have an app that may have the lumens and uniformity ratio for your applicaiton
      https://www.ies.org/education/ies-li...reference-app/
      If not, most wholesale houses have a lighting department and they can assist, esp if you purchase product from them.
      However, the NEC does cover the "low voltage" portion. Just because its low voltage does not mean it low power (example car battery)
      If you exceed the limits in NEC article 725, for a class 2 circuit (100VA) then you must use a chapter 3 wiring method.
      you might be better off using a 120V luminare, run a small size branch circuit of 15 or 20 amps.
      Moderator-Washington State
      Ancora Imparo

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        #4
        Originally posted by tom baker View Post
        ... you might be better off using a 120V luminare ...
        For large parking lots, it's most economical to use the highest voltage available -- 208, 240 or 277 volts. Higher voltages enable you to use smaller wire.

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          #5
          Originally posted by Jim Gann View Post
          What is the best resource for this information without purchasing the 2017 NEC book?
          Besides what the others have said, Fl isn't using the 2017 either.

          Roger
          Moderator

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            #6
            NEC is available on line at NFPA.
            Moderator-Washington State
            Ancora Imparo

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              #7
              Originally posted by drcampbell View Post
              For large parking lots, it's most economical to use the highest voltage available -- 208, 240 or 277 volts. Higher voltages enable you to use smaller wire.
              For LED lighting the higher voltages are not always required, it just depends on the luminaire amps and distances
              Moderator-Washington State
              Ancora Imparo

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                #8
                The best source to reference is the local code enforcement officials. Parking lot lighting requirements vary greatly between jurisdictions. Lots of rural areas may not have any parking lot min. light level requirements. Others may have a dark sky ordinance / limit how much backlight/uplight/glare (BUG ratings) you can have. If you're not already, recommend having the site lighting calc'd to also make sure you're not bleeding light into adjacent properties or roadways - asking for a lawsuit from an annoyed neighbor, or someone that gets in an accident because their visibility was limited due to glare.

                Another thing to watch out for is height limitations the AHJ will allow for the poles (although with LV 40W fixtures I'm guessing you're doing building mounted lighting?).

                Last thing I'll mention, which isn't REALLY related to your original post, is to make sure your pole locations will be OK with the utilities and transportation services near your project - primarily the electric company and the railroad company (if applicable). I've been burned a couple of times for encroaching on their easements.
                I'm offended.

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