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Thread: NFPA 70E Arc Flash Boundries

  1. #1

    NFPA 70E Arc Flash Boundries

    Does 70E require arc flash boundries marked on the floor. That is are the boundries marked with something like yellow(caution) paint. Before any work begins are the boundries are physically visible.

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    No...

    The arc flash boundary alerting requirement is met by it being displayed on the AF label.
    It's a good idea, IMO, to use additional techniques to identify the boundary, but along with that then there would need to be sitewide training so everyone could know what's being done (i.e. red/yellow/orange paint for AFB)
    John M

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    Quote Originally Posted by mjc1060 View Post
    Does 70E require arc flash boundries marked on the floor. That is are the boundries marked with something like yellow(caution) paint. Before any work begins are the boundries are physically visible.
    There is no need to mark the floor, just as there is no need to permanently mark working clearances. The AF boundary only exists when someone is "interacting in a manner that would cause an arc" not just simple interaction.

    Many Electrical Safe Work Practices programs require the use of 'caution tape' or other portable/temporary barricades.
    Just because you can, doesn't mean you should.

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    what if electrical panels are in an employee break room. how much room has to be between the panels and a lunch table ?

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    Quote Originally Posted by the blur View Post
    what if electrical panels are in an employee break room. how much room has to be between the panels and a lunch table ?
    None, other than the NEC standard clear space.
    The arc flash boundary only applies when there is 'interaction that can cause an arc'.
    Just because you can, doesn't mean you should.

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    Interaction

    Quote Originally Posted by jim dungar View Post
    There is no need to mark the floor, just as there is no need to permanently mark working clearances. The AF boundary only exists when someone is "interacting in a manner that would cause an arc" not just simple interaction.

    Many Electrical Safe Work Practices programs require the use of 'caution tape' or other portable/temporary barricades.
    How would you define a simple interaction verses an interaction that would cause an arc?

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    Quote Originally Posted by al View Post
    How would you define a simple interaction verses an interaction that would cause an arc?
    Examples of interactions that may cause an arc are the tasks listed in the task tables.

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    NFPA70E is fraught with what needs to be done but, purposely, there is not much detail on how to accomplish it.

    See the NFPA70E definition of Arc Flash Hazard.
    Informational Note #1 says normal operation is normally not an issue, Note #2 is the reference for Zog's posting directing you to the task tables.

    But then to make things clearer (?), the committee added Note #2 to 130.7(A), which effectively says; in the experience of the [NFPA70E] committee members normal operation of properly maintained enclosed equipment <600V is not likely a hazard.

    So there is no single correct answer, but, statistically it is worse to be operating equipment, than it is walking past or simply sitting in the same room with it.
    Just because you can, doesn't mean you should.

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    No. Only the equipment itself must be labeled, and only for when the incindent energy is larger than 1.2 cal/cm sq. (see attached NFPA 130.5(C)

    Attachment 7051

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    Quote Originally Posted by kenaslan View Post
    No. Only the equipment itself must be labeled, and only for when the incindent energy is larger than 1.2 cal/cm sq. (see attached NFPA 130.5(C)
    130.5(C) makes absolutely no mention of an incident energy level cut off /exclusion. If you are going to examine, service, adjust, or maintain it, while energized, it needs to be labeled.
    Just because you can, doesn't mean you should.

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