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Thread: 30-A Branch Circuit for 200W LED High Bays

  1. #1
    Join Date
    Sep 2018
    Location
    Houston, Texas
    Posts
    2

    30-A Branch Circuit for 200W LED High Bays

    I been told that I can not install 30A breaker on a Lighting circuit other than 20A
    NEC 210.21(A) talks that when a Lampholder is connected to a circuit rated above 20A, the lampholder shall be of the Heavy-Duty type. not less than 660W or 750W depending of the material.
    I think this was written for the use of the old style Metal Halide or High Pressure Sodium Lamps.
    And this the exception on NEC 210.23(B) as long the load does not exceed 80 percent of the branch-circuit ampere rating.

    My question is: where the T5HO (6 or 8 lamps) and LED (150W to 350W) high bays stand? Those can not be called Heavy Duty?
    Are these called equal to Metal Halide lamps not allowed to be on 30A breaker with #10 AWG wire?

    Please help me out & thanks in advance.

  2. #2
    Join Date
    Dec 2006
    Location
    Chapel Hill, NC
    Posts
    33,756
    IMO, you are stuck with 20 amps unless you have an Led acorn type which uses the heavy duty lampholder but the wattage part will get you.
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  3. #3
    Join Date
    Sep 2018
    Location
    Houston, Texas
    Posts
    2
    So the T5HO and LED high bays can be called
    heavy duty? even if they are the replacement for the obsolete/discontinue Metal Halide Lamps.

  4. #4
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    38,252
    (A) Lampholders.
    Where connected to a branch circuit having a rating in excess of 20 amperes, lampholders shall be of the heavy-duty type. A heavy-duty lampholder shall have a rating of not less than 660 watts if of the admedium type, or not less than 750 watts if of any other type.
    My interpretation is that the lampholders (title of the section) can't connect to the branch circuit unless they meet the conditions mentioned. This means majority of LED's and linear fluorescent tubes connect to a ballast/driver not the branch circuit.

    HID luminaires we often call that thing inside ballast, it actually is an autotransformer - which means the lampholder is connected to the branch circuit.

    Same rule has been around AFAIK since back when 500 watt incandescant lamps in a heavy duty mogul base lampholder were common.
    I live for today, I'm just a day behind.

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