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Thread: How to Comply w/NEC 2017 690.11 Arc-Fault Circuit Proection (DC)-Strings > 3 Modules?

  1. #11
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    I'm told the latest inverters provide AF protection?

    ~RJ~

  2. #12
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    Quote Originally Posted by romex jockey View Post
    I'm told the latest inverters provide AF protection?

    ~RJ~
    Many of them, yes.

  3. #13
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    If you really want to get into the nuts and bolts UL standard 1699B used to list PV arc fault equipment describes the type of arc fault that is protected against and it is series only.

    Series arc faults were determined to occur more often than parallel arc faults and to end a parallel arc fault you have to open the source side. Since that means module level disconnects no one wants to go there just to stop parallel arc faults. Disconnecting the load can make parallel arc faults worse so it's a conundrum. Also, parallel arc faults are just developing L-L or L-G faults and those have at least limited protection from OCPD.

  4. #14
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    A series hot spot aka-arc is literally 1/2 my service calls.

    As to 690.12, it makes sense , given DC's ionization qualities vs. AC



    ~RJ~

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