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Thread: Exposed negative side of LED Power Supply

  1. #1
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    Exposed negative side of LED Power Supply

    Two part question.

    Looking at a project where I might need to expose about 1" of the negative side of constant current LED power supply about 50' in the air. This bothers me, I'm wondering if this is practical and if it is legal.

    I could exposed the neutral side of the 115VAC line, but is this legal ?

    thanks in advance.

  2. #2
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    For what purpose?

    Here's what you are faced with regarding the 115V AC circuit...
    110.27 Guarding of Live Parts.

    (A) Live Parts Guarded Against Accidental Contact.

    Except as elsewhere required or permitted by this Code,
    live parts of electrical equipment operating at 50 volts or
    more shall be guarded against accidental contact by approved
    enclosures or by any of the following means:
    (1) By location in a room, vault, or similar enclosure that is
    accessible only to qualified persons.
    (2) By suitable permanent, substantial partitions or screens
    arranged so that only qualified persons have access to
    the space within reach of the live parts. Any openings
    in such partitions or screens shall be sized and located
    so that persons are not likely to come into accidental
    contact with the live parts or to bring conducting objects
    into contact with them.
    (3) By location on a suitable balcony, gallery, or platform
    elevated and arranged so as to exclude unqualified
    persons.
    (4) By elevation above the floor or other working surface
    as shown in 110.27(A)(4)(a) or (b) below:
    a. A minimum of 2.5 m (8 ft) for 50 to 300 volts
    b. A minimum of 2.6 m (81⁄2 ft) for 301 to 600 volts

    (B) Prevent Physical Damage. In locations where electrical
    equipment is likely to be exposed to physical damage,
    enclosures or guards shall be so arranged and of such
    strength as to prevent such damage.

    (C) Warning Signs. Entrances to rooms and other guarded
    locations that contain exposed live parts shall be marked
    with conspicuous warning signs forbidding unqualified persons
    to enter. The marking shall meet the requirements in
    110.21(B).

    Informational Note: For motors, see 430.232 and 430.233.
    For over 600 volts, see 110.34.
    Don't know the details of your LED driver. It may fall under Article 725. But offhand, I do no know of any Code requirements for insulation integrity or conductor exposure for less than 50V wiring.
    I will have achieved my life's goal if I die with a smile on my face.

  3. #3
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    Is the negative side grounded?

    Sent from my XT1585 using Tapatalk

  4. #4
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    Quote Originally Posted by Smart $ View Post
    For what purpose?

    Here's what you are faced with regarding the 115V AC circuit...


    Don't know the details of your LED driver. It may fall under Article 725. But offhand, I do no know of any Code requirements for insulation integrity or conductor exposure for less than 50V wiring.

    An EU firm has been selling a product that I think has an exposed neutral, didn't think it was correct - we insulate both sides. If the neutral side of the circuit is disconnected the exposed conductor would go to 115VAC and be a hazard.


    We were thinking of trying the same idea of an exposed conductor with a Class 2 LED circuit. I have a gut feeling this is a bad idea, but I can't pin point why.

  5. #5
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    Quote Originally Posted by GoldDigger View Post
    Is the negative side grounded?

    Sent from my XT1585 using Tapatalk
    probably not - I don't think you would commonly ground the negative side of LED power supply.

  6. #6
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    Class 2 Circuit Exposed

    Is it possible to have an exposed Class 2 circuit or return.

    I've seen this on hanging lighting fixtures in restaurants - where there are two exposed conductors.

    But I see nothing about this in Article 725.

  7. #7
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    Quote Originally Posted by SAAPI View Post
    Is it possible to have an exposed Class 2 circuit or return.

    I've seen this on hanging lighting fixtures in restaurants - where there are two exposed conductors.

    But I see nothing about this in Article 725.
    Perhaps manufactured and sold as an assembly, or field assembled per manufacturers instructions...

    410.6 Listing Required. All luminaires, lampholders, and
    retrofit kits shall be listed.
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  8. #8
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    What's the spec on the LED ballast?

  9. #9
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    Specification on the Ballast

    Quote Originally Posted by Electric-Light View Post
    What's the spec on the LED ballast?
    This is one unit we use.

    I see the negative side of the output tied to ground through a capacitor - tying the negative side of the output to ground would defeat this.

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