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Re: 277 volt vs 120 volt lighting

Discussion in 'Electrical Engineering' started by Frank White, Apr 7, 2006.

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  1. Frank White

    Frank White Guest

    If the building has a 480V/277V service and you have a lot of lights
    to install, then the contractor can use smaller wire with 277V
    lighting but will have to use more expensive lighting panels.
    Also you will not be putting the extra current load on your existing
    step down transformers if you use 277V.

    I would talk to the contractor and the owner and ask them each to
    present thier case. As far as the lighting goes, there really isnt
    much difference. 120V installations tend to be cheaper and safer
    if you have enough power at that voltage.


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  2. And conversely, if you don't already have a 480/277V service, 277V
    lighting make no sense at all. It is mainly a convenience for
    facilities that have 3 phase 480V 4 wire service because phase to
    neutral is 277V, so no transformer is needed. If your facility has 1
    phase service, or 208V 3 phase service, then 120V lighting is what you
    want. The electrician probably already knows this. The owner probably
    has no clue.
     
  3. Ryan Evans

    Ryan Evans Guest

    Is the 480V a wye (3 phase + neutral)? If so, you don't need a transformer
    for the 277.

    RE
     
  4. SQLit

    SQLit Guest

    Your missing the point. if the service is 480 3 phase then you need a
    transformer for the 120 loads. depending on the load on the transformer the
    lighting might push it up one size.

    other than losses through the transformer to step down the voltage to 120 I
    am not aware of any real difference.

    With out a intimate knowledge of the installation and rate structure and a
    couple of hundred other things I know of no good way to make a
    recommendation.

    Fixtures will cost the same no matter what voltage you buy.
     
  5. Beachcomber

    Beachcomber Guest

    The main advantage of 277V. lighting circuits (assuming 277V is
    readily available) is that you have less voltage drop, the means to do
    longer runs (from panelboard to fixture), and more fixtures can be
    attached per circuit breaker (vs. 120V lighting circuits). In the
    long run, if done properly, this leads to economies of scale and
    allows for a cheaper, more economical, and efficient installation.

    The 277V. circuits use less current (for equal amounts of light on
    the equivalent 120V circuits) and you may be able to get away with
    installing a smaller lighting panelboard than otherwise might be
    necessary.

    Beachcomber
     
  6. Guest

    | The main advantage of 277V. lighting circuits (assuming 277V is
    | readily available) is that you have less voltage drop, the means to do
    | longer runs (from panelboard to fixture), and more fixtures can be
    | attached per circuit breaker (vs. 120V lighting circuits). In the
    | long run, if done properly, this leads to economies of scale and
    | allows for a cheaper, more economical, and efficient installation.
    |
    | The 277V. circuits use less current (for equal amounts of light on
    | the equivalent 120V circuits) and you may be able to get away with
    | installing a smaller lighting panelboard than otherwise might be
    | necessary.

    To clarify, you could have more lights on the same circuit, reducing the
    number of circuits and thus the number of slots in the panel. The higher
    voltage panels are slightly larger for the same number of circuits when
    compared to the 3/4 inch Square-D QO/NQOD and Cutler-Hammer CH series if
    you went with 208/120 for everything. For 480/277 you would use panels
    like Square-D NF or Cutler-Hammer PRL2.
     
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