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Overhead switch arc gap

Discussion in 'IEEE 1584 - IEEE Guide for Performing Arc-Flash Ha' started by ekalbs4, Jul 9, 2009.

  1. ekalbs4 New Member

    When using IEEE 1584 Table 4, does an overhead switch on a utility 12.47 kV distribution circuit fall under the open air category or the switchgear category?

    I figure that open air is applicable and that switchgear is intended for enclosed type equipment, which this is not.
    ekalbs4, Jul 9, 2009
    #1

  2. acobb Well-Known Member

    If it is an open air break switch, then it shoud be analyized as open air.

    Alan
    acobb, Jul 9, 2009
    #2

  3. acobb Well-Known Member

    And if it is utility owned open air equipment, I would use Arcpro and not 1584 for the numbers.

    Sorry for the double post.

    Alan
    acobb, Jul 9, 2009
    #3

  4. ekalbs4 New Member

    Can you please explain why the preference for Arcpro?
    ekalbs4, Jul 10, 2009
    #4

  5. acobb Well-Known Member

    The open air calcs for over 1000 volts in 1584 assume a 3 phase fault. The NESC treats everything as a single phase fault because of the larger phase spacings. Arcpro was used to create the tables in the NESC and models single phase arcs in open air. We only use 1584 for enclosures and voltages less than 1000 volts.
    acobb, Jul 11, 2009
    #5

  6. ekalbs4 New Member

    Great feedback, thank you very much!
    ekalbs4, Jul 13, 2009
    #6

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