Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Antiquated Switchgear: Arc Flash Hazards

  1. Jul 20, 2015 #1


    User Avatar
    Gold Member

    I am reviewing the LV and MV switchgear and their protection path within our plant. A significant number of critical breakers and enclosures are 20-30 years old and are in need of replacement. In addition to considering the operational advantages of upgrading the gear, I am trying to find information related to Arc Flash hazards and whether older gear has a higher chance of producing an arc flash.

    I have searched the NFPA 70E for information and cannot find anything related to my question; most of the standards are related to compliance, not analyzing root causes for the flashes themselves. Does anyone know of a reliable source that discusses whether older gear is more susceptible to arc flashes, or if there is no significant risk at all?
  2. jcsd
  3. Jul 20, 2015 #2


    Staff: Mentor

  4. Jul 21, 2015 #3


    User Avatar
    Gold Member

  5. Jul 21, 2015 #4


    User Avatar
    Education Advisor
    Gold Member

    The actual guide for calculations are taken from the IEEE standards: https://standards.ieee.org/findstds/standard/1584-2002.html is one source. The NEC 70E document is a safety document that helps or pertains to electricians or trained personal to work with the proper safety wear or simply power down the equipment if the Arc Flash values are too high.

    Sadly most Electrical Engineers do not reference or learn how to apply this document to actually calculate these values by hand (many contracts or specifications don't allow this either, but insist on a software model and calculation), but use software and model these calculations based upon current plant conditions and configurations. Adding a large motor or changing out a service transformer necessitates a complete recalculation of the whole system.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Antiquated Switchgear: Arc Flash Hazards