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  1. Replies
    7$$
    Views
    983

    It is, but then again people punch holes in...

    It is, but then again people punch holes in pressurized gasoline pipelines in Mexico to get free gas. There is no limit to how stupid humans can get when they think they can get some free stuff.
  2. Replies
    7$$
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    501

    I thought that DC Optimizers let you mount...

    I thought that DC Optimizers let you mount modules anywhere? Have I been lied to again? What's next, bifacial modules can't collect the sunlight from the other side of the world on the backside at...
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    6$$
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    438

    All the panels between where the PV interconnects...

    All the panels between where the PV interconnects and the utility POCC have to meet the 705.12 requirements. If the home panel has a 200A main OCPD changing the OCPD in the pedestal will not satisfy...
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    5$$
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    669

    Should have put a rooster sticker on it and said...

    Should have put a rooster sticker on it and said it's a feature of this model.

    NEC 690.4(E) says you can't install an inverter in a bathroom. The only restriction I know of.
  5. AHJ passes something that the contractor thinks...

    AHJ passes something that the contractor thinks might be a code violation, either because the AHJ missed it, does not understand why it is incorrect, or just doesn't care about that one thing, etc....
  6. Replies
    4$$
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    539

    It depends.... In general, a non-fusable...

    It depends....

    In general, a non-fusable disconnect protected upstream by any correctly rated fuse or circuit breaker will give an SCCR of 10kA. If you have more available fault current than that...
  7. Enjoy that you were allowed to do this for years...

    Enjoy that you were allowed to do this for years even though it was not following the code. But now you are being held to the NEC and the AHJ is correct. There was a TIA issued to allow center-fed...
  8. Replies
    7$$
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    768

    A reverse power relay is a protection system that...

    A reverse power relay is a protection system that uses a protection relay to monitor the power flow at the POCC. If the power flow reverses and starts to send power to the utility it trips the PV...
  9. Replies
    27$$
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    1,573

    There was a time in the dark past, 20,000 PV...

    There was a time in the dark past, 20,000 PV years ago (10 real years) when PV modules were so expensive that inverters were always sized to prevent clipping and therefore were under producing 99% of...
  10. Replies
    27$$
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    1,573

    There is no guidance on what current to use, and...

    There is no guidance on what current to use, and the output of an inverter is highly variable.
  11. Replies
    27$$
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    1,573

    I've found a lot of variety in doing the voltage...

    I've found a lot of variety in doing the voltage drop calc. Since it's not a code issue we are left to choose values based on experience and how close we want to get to losing everything on the...
  12. Replies
    27$$
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    1,573

    We want to look at the voltage window we have to...

    We want to look at the voltage window we have to work with, so we compare the maximum operating AC voltage of the inverter with the max AC voltage the utility is supposed to limit their system to in...
  13. Replies
    7$$
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    768

    ggunn, are you trying to use the SolarEdge Smart...

    ggunn, are you trying to use the SolarEdge Smart Energy Management system to create a no-export system, maybe backed up with a reverse power relay? I'd like to meet the contractor that got that to...
  14. Replies
    27$$
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    1,573

    The ANSI B range upper end is 508V. That means...

    The ANSI B range upper end is 508V. That means you get at most 11V of voltage drop to work with before you hit 529V . Based on a nominal voltage of 480V that gives you 2.29% voltage drop. Even the...
  15. Replies
    27$$
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    1,573

    Section 130.5 of the 2019 CA Energy Standard...

    Section 130.5 of the 2019 CA Energy Standard covers electrical distribution system voltage drop. Source to load the combined voltage drop through feeders and branch circuits has to be 5% or less, not...
  16. Possible, but a lot of assembly required unless...

    Possible, but a lot of assembly required unless someone is selling an integrated unit. The GE HPC is a contender except no visible blades. This is the reason 240.67 has delayed implementation, the...
  17. Replies
    21$$
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    2,703

    Plenty of PEs out there who are running stamp...

    Plenty of PEs out there who are running stamp shops. A contractor once told me of a PE up in Napa who was retired who would stamp his plans for a few bottles of good wine. Very hard to find and...
  18. How to comply with NEC 240.67 Arc Energy Reduction in 2020

    I'm looking at the 2017 NEC 240.67 and trying to figure out what is available to satisfy this requirement along with the other requirements for PV systems. Currently there is no fused disconnect...
  19. My guess is that he did a curve fit of the data...

    My guess is that he did a curve fit of the data and did not like it versus the same data plot using his calculated values. I have not had a chance to compare the results of the two methods myself yet...
  20. Replies
    14$$
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    1,856

    I would still bounce it with a comment. It's...

    I would still bounce it with a comment. It's poorly documented and two pages of comments here on the subject show it's unclear.
  21. The OP did say the question was calculation of...

    The OP did say the question was calculation of the current in accordance with 690.8(A)(1)(2). I gave an answer that matched the request.
  22. Replies
    27$$
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    1,573

    The AC drop on PV systems is usually limited to...

    The AC drop on PV systems is usually limited to around 2% so the inverter does not trip off on overvoltage. Sometimes PV designers list a total voltage drop number that sums the AC and DC voltage...
  23. You want the highest three hour average Isc for...

    You want the highest three hour average Isc for the year.

    There is an article about this in Solar Professional magazine 11.4 (July-Aug 2018) that covers the calculations using software. SAM can...
  24. Replies
    8$$
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    984

    I would say the "load charger"is not a charger...

    I would say the "load charger"is not a charger but either a DC power supply or an AC inverter. Morningstar does make an inverter.
  25. Replies
    7$$
    Views
    1,082

    If an unfused disconnect is used make sure it is...

    If an unfused disconnect is used make sure it is rated for the available fault current. Most allow up to 10kAIC when protected by any upstream OCPD but to get a higher rating the OCPD and the...
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