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2020 NEC 250.25

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    2020 NEC 250.25

    PV installers... put the green screw in! Thank you CMP 5... you got it right.

    #2
    For those of us without the 2020 can you elaborate?
    Rob

    Moderator

    All responses based on the 2017 NEC unless otherwise noted

    Comment


      #3
      Not sure what this is about-- wrong article #???

      250.25 Grounding Systems Permitted to Be Connected on the Supply Side of the Disconnect.

      The grounding of systems connected on the supply side of the service disconnect, as permitted in 230.82, that are in enclosures separate from the service equipment enclosure shall comply with 250.25(A) or (B).

      250.25(A) Grounded System.

      If the utility supply system is grounded, the grounding of systems permitted to be connected on the supply side of the service disconnect and are installed in one or more separate enclosures from the service equipment enclosure shall comply with the requirements of 250.24(A) through (D).

      250.25(B) Ungrounded Systems.

      If the utility supply system is ungrounded, the grounding of systems permitted to be connected on the supply side of the service disconnect and are installed in one or more separate enclosures from the service equipment enclosure shall comply with the requirements of 250.24(E).
      They say I shot a man named Gray and took his wife to Italy
      She inherited a million bucks and when she died it came to me
      I can't help it if I'm lucky

      Comment


        #4
        Sorry...for 2...maybe 3 Code cycles there has been confusion, debate (numerous threads here), and argument across the country on whether a supply-side connected PV Disconnect needed to have a Main Bonding Jumper per 250.24(B) like a Service Disconnect. But...a PV disconnect is not a "Service Disconnect", nor is a PV system a "Service", CMP 4 asserted. With the new section 250.25 in the 2020 NEC, the language now requires the Main Bonding Jumper to be installed per 250.24(B)...and also requires the installation to comply with 250.24(D) and the installation of a GEC to the enclosure for systems connected supply-side of the service disconnect as permitted in 230.82. {For the rarely installed supply-side ungrounded service interconnection, follow 250.24(E)}

        A 705.12 (705.11 in the 2020) supply-side connected Interconnected Power Production Source is exposed to the same dangerous fault currents that a service disconnect is, so it is important to bond and ground like a service disconnect.

        I can not think of a arrangement when following 250.24 (A) through (D) where is is dangerous to bond and ground a supply-side connected Interconnected Power Production Source like a service. The fault current path to the Utility source though this bonding and grounding makes the installation safer.

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