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Thread: Panelboard main terminal barriers

  1. #1
    Join Date
    Dec 2013
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    Denver, CO
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    Panelboard main terminal barriers

    408.3(A)(2) Service Panelboards, Switchboards, and Switchgear. Barriers shall be placed in all service panelboards, switchboards, and switchgear such that no uninsulated, ungrounded service busbar or service terminal is exposed to inadvertent contact by persons or maintenance equipment while servicing load terminations.

    I find this barrier requirement wording too vague, and I don’t find any help in reading UL67 5.4.2.

    For example, assume a MLO loadcenter (and that the exception of 408.36 does not apply):

    1. Does “service terminal” include main lugs?

    (2. Even with barriers on the main lugs, how would barriers on busbars sections be accomplished, i.e., exposed busbars with no breakers on them?)

    3. Some manufacturers must also be confused because they do not include barriers with MLO loadcenters. Not to mention any names, but see the label below which conspicuously omits MLOs when ordering barrier kits…
    Name:  tmp eaton label.jpg
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    Can anyone shed light on MLO barriers? Thank you in advance

  2. #2
    Join Date
    Jul 2003
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    This is for services. If you have a panel that is not a service then it can be de-energized at the source. Unless the MLO was a service with up to 6 service disconnects the protection is not required.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

  3. #3
    Join Date
    Dec 2013
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    ahhh... so Eaton included the part no. to order in case it was converted to main breaker and used as a service panel. Thanks much!

  4. #4
    Join Date
    Dec 2007
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    Quote Originally Posted by infinity View Post
    This is for services. If you have a panel that is not a service then it can be de-energized at the source. Unless the MLO was a service with up to 6 service disconnects the protection is not required.
    Which brings up the question of how do you handle cases where up to six breakers are installed as the service disconnect? You not only have the main lugs to place a barrier on, but the bus is energized as well.

    This is not a problem with many "loadcenters" because if you look at the instructions they typically are only suitable for use as service equipment when a main breaker is installed. Get into commercial/industrial panelboards and switchboards and things can be different.
    I live for today, I'm just a day behind.

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