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    <font face="Helvetica, Arial, sans-serif">Jason, this is the same
      rationale I have heard before-- and sadly parroted myself before
      seeing the light-- but I agree that it's inaccurate. 90.8(A) is
      the only "futureproofing" thing in the NEC that I know of, but I
      take it as an "FYI, if you oversize now it allows for easier
      expansion later" rather than a requirement. After all, no one runs
      #4 for a 20A circuit within a 4" conduit on the assumption that
      someone later may want to add 38 more conductors into that same
      raceway. And if you trip a main breaker with the Tesla fast
      charger you just installed in the garage, it's hard to blame the
      original electrician for lack of foresight...  <br>
      <br>
      DKC <br>
      <br>
       <br>
      <br>
      <br>
    </font>
    <div class="moz-cite-prefix">On 2014/3/5, 11:04, Jason Szumlanski
      wrote:<br>
    </div>
    <blockquote
cite="mid:CAJJtG3okh4FHAjWWGF3Xq-RDkdfq1LPqzawaAi9RYp-sNHynzg@mail.gmail.com"
      type="cite">
      <div dir="ltr">
        <div class="gmail_default"
          style="font-family:verdana,sans-serif">I thought one of the
          the rationale for the upsized conductor between panelboards in
          series was to account for the possibility that the conductor
          could be later tapped with other loads or backfed from another
          PV source in theory. I never thought that rationale was
          reasonable - any future changes of this significance would
          need to be addressed at that time anyway.</div>
        <div class="gmail_default"
          style="font-family:verdana,sans-serif"><br>
        </div>
        <div class="gmail_default"
          style="font-family:verdana,sans-serif">I have found that AHJs
          are lenient and reasonable on this point if addressed in
          advance. It should only be an issue in NEC 2008 and 2011 if
          using a load side connection. If your jurisdiction allows it,
          a supply side connection should bypass this issue altogether.
          When using a subpanel to combine multiple inverter outputs,
          it's often the case that a load side connection is not
          possible in retrofit situations, at least in my experience.
          Even on a 1600A commercial main bus where the 120% rule is a
          non-factor, there are often prohibitive issues that make a
          supply-side connection much more cost effective. For example,
          I've run into manual generator switches or situations where it
          is impractical to move breakers to accommodate the proper
          backfed breaker location. </div>
        <div class="gmail_default"
          style="font-family:verdana,sans-serif"><br>
        </div>
        <div class="gmail_default"
          style="font-family:verdana,sans-serif">By the way, we've had
          this discussion before. Search the archives for:</div>
        <div class="gmail_default"><font face="verdana, sans-serif">"sizing
            a sub-panel used to combinemultipleinverter outputs"</font><br>
        </div>
        <div><br>
        </div>
        <div>
          <div class="gmail_default"
            style="font-family:verdana,sans-serif">
            (there are several prior discussions on the subject)</div>
          <br>
        </div>
        <br>
        <div id="WISESTAMP_SIG_gmail_session">
          <div
            style="font-size:13px;font-family:Verdana,Arial,Helvetica,sans-serif">
            <div style="margin:0px 0px 8px">
              <p style="margin:0px">
                <span><span>Jason Szumlanski</span></span></p>
              <div class="gmail_default"
                style="font-family:verdana,sans-serif;display:inline">Fafco
                Solar</div>
              <br>
               </div>
          </div>
        </div>
        <div class="gmail_extra"><br>
          <div class="gmail_quote">On Wed, Mar 5, 2014 at 10:30 AM, Dave
            Click <span dir="ltr"><<a moz-do-not-send="true"
                href="mailto:daveclick@fsec.ucf.edu" target="_blank">daveclick@fsec.ucf.edu</a>></span>
            wrote:<br>
            <blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
              <div bgcolor="#FFFFFF" text="#000000"> I think there's
                plenty of room to interpret the 2008 and 2011 NEC such
                that you don't need to upsize this conductor either.
                2008 690.64(B)(2) and 2011 705.12(D)(2) are both titled
                "bus or conductor," and as Brian points out below the
                currents aren't additive. As I understand it the 120%
                rule was because panelboard manufacturers weren't
                comfortable with exceeding 120% due to heat concerns
                under continuous operation (assuming a fully loaded
                panelboard). As for conductors, I wonder if that 120%
                was just to keep it consistent with the panelboard
                requirement, even though it would be safe at levels
                >120% as long as you're feeding from opposite ends.<br>
                <br>
                Also, since you seem to be talking about a good amount
                of PV with your 2 SolarEdge 20s, make sure your upstream
                breakers are OK to be backfed (up through and including
                the main, unless you've got a large, guaranteed
                baseload).<br>
                <br>
                DKC <br>
                <div>
                  <div class="h5"> <br>
                    <div>On 2014/3/5, 10:01, Brian Mehalic wrote:<br>
                    </div>
                    <blockquote type="cite">
                      <div dir="ltr">A very clarifying change is what
                        I'd call it! 
                        <div><br>
                        </div>
                        <div>First off, rather than being based on the
                          actual breaker size on the inverter output
                          circuit, calcs are instead based on 125% of
                          the inverter rated output current.<br>
                          <div><br>
                          </div>
                          <div>705.12(D)(2)(1) addresses "Feeders" - but
                            only applies when the inverter output
                            circuit connection is made somewhere other
                            than the opposite end of the feeder from the
                            utility supply.  This addresses concerns
                            about whether the feeder conductor needs to
                            be larger due to the presence of the
                            additional source of supply, and so long as
                            the inverter isn't connected to the feeder
                            in the middle of it then the existing
                            conductor size should be okay (because if it
                            is at the opposite end of the feeder than
                            there is nowhere where the utility and
                            inverter current will be additive).</div>
                        </div>
                        <div><br>
                        </div>
                        <div>705.12(D)(2)(3) addresses "Busbars" and
                          allows several options, including the familiar
                          "120% rule" as you stated in your original
                          post.  Also check out 705.12(D)(2)(3)(c) -
                          depending on the load breakers in the
                          subpanel, the 120% rule may not even need to
                          be used (if the sum of the inverter and load
                          breakers is less than or equal to the busbar
                          rating).</div>
                        <div><br>
                        </div>
                        <div>And remember, even if your AHJ hasn't
                          adopted 2014 yet it is worth having a
                          conversation with them to see if they'll allow
                          you to design the system based on the new Code
                          - after all, in a certain sense, the 2014 NEC
                          is what "they" meant the 2011 NEC to say!</div>
                        <div><br>
                        </div>
                        <div>Cheers,</div>
                      </div>
                      <div class="gmail_extra"><br clear="all">
                        <div>
                          <div dir="ltr">
                            <div><br>
                            </div>
                            <div>Brian Mehalic <br>
                              NABCEP Certified Solar PV Installation
                              Professional™ R031508-59
                              <div>IREC ISPQ Certified Affiliated
                                Instructor/PV US-0132<br>
                                <div><br>
                                </div>
                                <div>PV Curriculum Developer and
                                  Instructor
                                  <div>Solar Energy International<br>
                                    <a moz-do-not-send="true"
                                      href="http://www.solarenergy.org"
                                      target="_blank">http://www.solarenergy.org</a></div>
                                </div>
                              </div>
                            </div>
                          </div>
                        </div>
                        <br>
                        <br>
                        <div class="gmail_quote">On Tue, Mar 4, 2014 at
                          5:21 PM, Kirk <span dir="ltr"><<a
                              moz-do-not-send="true"
                              href="mailto:kirk@vtsolar.com"
                              target="_blank">kirk@vtsolar.com</a>></span>
                          wrote:<br>
                          <blockquote class="gmail_quote"
                            style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
                            <div dir="auto">
                              <div>Is this a code change in 2014 vs 2011
                                or merely a clarification? Vt has not
                                adopted 2014 yet. What was the original
                                rationale for the 120% rule to apply to
                                conductors in addition to a panel bus? <span><font
                                    color="#888888"><br>
                                    <br>
                                    Kirk Herander
                                    <div>VSE</div>
                                  </font></span></div>
                              <div>
                                <div>
                                  <div><br>
                                    On Mar 4, 2014, at 6:20 PM, Brian
                                    Mehalic <<a
                                      moz-do-not-send="true"
                                      href="mailto:brian@solarenergy.org"
                                      target="_blank">brian@solarenergy.org</a>>

                                    wrote:<br>
                                    <br>
                                  </div>
                                  <blockquote type="cite">
                                    <div>
                                      <div>If the subpanel is at the end
                                        if the feeder, and there are no
                                        taps in between the main and the
                                        sub then I don't see any reason
                                        that the conductors need to be
                                        any larger than 200 A as there
                                        is no where on the feeder
                                        conductors where grid and PV
                                        current will be additive. </div>
                                      <div><br>
                                      </div>
                                      <div>The changes in 705.12 in 2014
                                        address this in large part. <br>
                                        <br>
                                        Brian</div>
                                      <div><br>
                                        On Mar 4, 2014, at 2:41 PM,
                                        "Kirk Herander" <<a
                                          moz-do-not-send="true"
                                          href="mailto:kirk@vtsolar.com"
                                          target="_blank">kirk@vtsolar.com</a>>

                                        wrote:<br>
                                        <br>
                                      </div>
                                      <blockquote type="cite">
                                        <div>
                                          <div>
                                            <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Solaredge

                                                20 kw, 480 3-phase. Good
                                                point, but that may be
                                                irrelevant. The feed-in
                                                subpanel is also
                                                powering unrelated
                                                loads, which use the
                                                neutral as a conductor
                                                from the main panel. So
                                                4 conductors from the
                                                main.</span></p>
                                            <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"> </span></p>
                                            <div>
                                              <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Kirk

                                                  Herander</span></p>
                                              <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">VT

                                                  Solar, LLC</span></p>
                                              <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">dba

                                                  Vermont Solar
                                                  Engineering</span></p>
                                              <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">NABCEP<sup>TM

                                                  </sup>Certified
                                                  Inaugural Certificant</span></p>
                                              <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">NYSERDA-eligible

                                                  Installer</span></p>
                                              <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">VT

                                                  RE Incentive Program
                                                  Partner</span></p>
                                              <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><a
moz-do-not-send="true" href="tel:802.863.1202" value="+18028631202"
                                                    target="_blank">802.863.1202</a></span></p>
                                            </div>
                                            <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"> </span></p>
                                            <div>
                                              <div
                                                style="border-style:solid
                                                none
                                                none;border-top-color:rgb(181,196,223);border-top-width:1pt;padding:3pt
                                                0in 0in">
                                                <p class="MsoNormal"><b><span
style="font-size:10pt;font-family:Tahoma,sans-serif">From:</span></b><span
style="font-size:10pt;font-family:Tahoma,sans-serif"> <a
                                                      moz-do-not-send="true"
href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>
                                                    [<a
                                                      moz-do-not-send="true"
href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>]
                                                    <b>On Behalf Of </b>Allen
                                                    Frishman<br>
                                                    <b>Sent:</b>
                                                    Tuesday, March 04,
                                                    2014 4:32 PM<br>
                                                    <b>To:</b>
                                                    RE-wrenches<br>
                                                    <b>Subject:</b> Re:
                                                    [RE-wrenches]
                                                    conductors and the
                                                    120% rule</span></p>
                                              </div>
                                            </div>
                                            <p class="MsoNormal"> </p>
                                            <p class="MsoNormal"> what
                                              inverter(s) are you using?
                                                 In many cases the
                                              Neutral is not considered
                                              a Current Carying
                                              Conductor by the
                                              Manufacturer and therefore
                                              you only have 3 CCC.</p>
                                            <div>
                                              <div>
                                                <p class="MsoNormal"><i><span
style="font-size:10.5pt">Al Frishman</span></i><span
                                                    style="font-size:13.5pt"><br>
                                                  </span><span
                                                    style="font-size:13.5pt;color:rgb(3,1,0)">Aeon</span><span
style="font-size:13.5pt;color:rgb(255,151,0)">Solar</span><span></span></p>
                                                <p class="MsoNormal"><i><span
style="font-size:10.5pt"><a moz-do-not-send="true"
                                                        href="tel:%28917%29%20699-6641"
                                                        target="_blank">(917)
                                                        699-6641</a> -
                                                      cell</span></i><span
style="font-size:10.5pt"><br>
                                                    <i><a
                                                        moz-do-not-send="true"
href="tel:%28888%29%20460-2867" target="_blank">(888) 460-2867</a></i><br>
                                                    <i><a
                                                        moz-do-not-send="true"
href="http://www.aeonsolar.com/" target="_blank">www.aeonsolar.com</a></i></span><span></span></p>
                                              </div>
                                            </div>
                                            <p class="MsoNormal">  </p>
                                            <div>
                                              <div>
                                                <p class="MsoNormal">On
                                                  Mar 4, 2014, at 4:20
                                                  PM, Kirk Herander
                                                  wrote:</p>
                                              </div>
                                              <p class="MsoNormal"><br>
                                                <br>
                                              </p>
                                              <div>
                                                <div>
                                                  <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Approx..

                                                      50 – 60ft.</span><span></span></p>
                                                </div>
                                                <div>
                                                  <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"> </span><span></span></p>
                                                </div>
                                                <div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Kirk

                                                        Herander</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">VT

                                                        Solar, LLC</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal">
                                                      <span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">dba

                                                        Vermont Solar
                                                        Engineering</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">NABCEP<sup>TM<span> </span></sup>Certified

                                                        Inaugural
                                                        Certificant</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">NYSERDA-eligible

                                                        Installer</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal">
                                                      <span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">VT

                                                        RE Incentive
                                                        Program Partner</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><a
moz-do-not-send="true" href="tel:802.863.1202" value="+18028631202"
                                                          target="_blank">802.863.1202</a></span><span></span></p>
                                                  </div>
                                                </div>
                                                <div>
                                                  <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"> </span><span></span></p>
                                                </div>
                                                <div>
                                                  <div
                                                    style="border-style:solid
                                                    none
                                                    none;padding:3pt 0in
                                                    0in">
                                                    <div>
                                                      <p
                                                        class="MsoNormal"><b><span
style="font-size:10pt;font-family:Tahoma,sans-serif">From:</span></b><span><span
style="font-size:10pt;font-family:Tahoma,sans-serif"> </span></span><span
style="font-size:10pt;font-family:Tahoma,sans-serif"><a
                                                          moz-do-not-send="true"
href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a><span> </span><a
moz-do-not-send="true"
                                                          href="mailto:[mailto:re-wrenches-bounces@lists.re-wrenches.org]"
target="_blank">[mailto:re-wrenches-bounces@lists.re-wrenches.org]</a><span> </span><b>On

                                                          Behalf Of<span> </span></b>Ray

                                                          Walters<br>
                                                          <b>Sent:</b><span> </span>Tuesday,

                                                          March 04, 2014
                                                          4:05 PM<br>
                                                          <b>To:</b><span> </span>RE-wrenches<br>
                                                          <b>Subject:</b><span> </span>Re:

                                                          [RE-wrenches]
                                                          conductors and
                                                          the 120% rule</span><span></span></p>
                                                    </div>
                                                  </div>
                                                </div>
                                                <div>
                                                  <p class="MsoNormal"><span> </span></p>
                                                </div>
                                                <div>
                                                  <div>
                                                    <p class="MsoNormal"><span>What

                                                        is the length of
                                                        the conduit to
                                                        the subpanel?
                                                        That will
                                                        determine
                                                        whether to apply
                                                        the derates.<br>
                                                        <br>
                                                        <br>
                                                      </span></p>
                                                  </div>
                                                  <pre><span>R.Ray Walters</span></pre>
                                                  <pre><span>CTO, Solarray, Inc</span></pre>
                                                  <pre><span>Nabcep Certified PV Installer, </span></pre>
                                                  <pre><span>Licensed Master Electrician</span></pre>
                                                  <pre><span>Solar Design Engineer</span></pre>
                                                  <pre><span><a moz-do-not-send="true" href="tel:303%20505-8760" value="+13035058760" target="_blank">303 505-8760</a></span></pre>
                                                  <div>
                                                    <p class="MsoNormal"><span>On

                                                        3/4/2014 1:34
                                                        PM, Kirk
                                                        Herander wrote:</span></p>
                                                  </div>
                                                </div>
                                                <blockquote
                                                  style="margin-top:5pt;margin-bottom:5pt">
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Whether

                                                        or not a further
                                                        derate has to be
                                                        applied is the
                                                        killer here, as
                                                        I am working
                                                        with existing
                                                        panels and
                                                        conductors. In
                                                        an old Code
                                                        Corner(HP140) J.
                                                        Wiles goes
                                                        through a
                                                        similar scenario
                                                        and calls out
                                                        the allowable
                                                        current rating
                                                        and conductor in
                                                        310.15, but
                                                        makes no mention
                                                        of applying
                                                        additional
                                                        derate factors.
                                                        The .8 derate
                                                        for 4-6
                                                        conductors(l1,l2,l3,
                                                        & n) will
                                                        put the existing
                                                        4/0 cable
                                                        between feed-in
                                                        and main panel
                                                        at 208 amps,
                                                        less than the
                                                        allowable 217.
                                                        I’d hate to need
                                                        to upsize the
                                                        wire to 250 mcm.</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"> </span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">Kirk

                                                        Herander</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">VT

                                                        Solar, LLC</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal">
                                                      <span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">dba

                                                        Vermont Solar
                                                        Engineering</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">NABCEP<sup>TM<span> </span></sup>Certified

                                                        Inaugural
                                                        Certificant</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">NYSERDA-eligible

                                                        Installer</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal">
                                                      <span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)">VT

                                                        RE Incentive
                                                        Program Partner</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"><a
moz-do-not-send="true" href="tel:802.863.1202" value="+18028631202"
                                                          target="_blank">802.863.1202</a></span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span
style="font-size:14pt;font-family:Calibri,sans-serif;color:rgb(31,73,125)"> </span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><b><span
style="font-size:10pt;font-family:Tahoma,sans-serif">From:</span></b><span><span
style="font-size:10pt;font-family:Tahoma,sans-serif"> </span></span><span
style="font-size:10pt;font-family:Tahoma,sans-serif"><a
                                                          moz-do-not-send="true"
href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a><span> </span>[<a
moz-do-not-send="true"
                                                          href="mailto:re-wrenches-bounces@lists.re-wrenches.org"
target="_blank">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>]<span> </span><b>On

                                                          Behalf Of<span> </span></b>Jason

                                                        Szumlanski<br>
                                                        <b>Sent:</b><span> </span>Tuesday,

                                                        March 04, 2014
                                                        2:57 PM<br>
                                                        <b>To:</b><span> </span>RE-wrenches<br>
                                                        <b>Subject:</b><span> </span>Re:

                                                        [RE-wrenches]
                                                        conductors and
                                                        the 120% rule</span><span></span></p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span> </span></p>
                                                  </div>
                                                  <div>
                                                    <div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal"><span
style="font-family:Verdana,sans-serif">Both the bus and conductors need
                                                          to be rated
                                                          for 217 amps
                                                          minimum. As
                                                          you mentioned,
                                                          the bus is not
                                                          a problem. The
                                                          way I
                                                          interpret it,
                                                          the conductor
                                                          size required
                                                          would be after
                                                          derate factors
                                                          are applied.
                                                          The rating of
                                                          the conductor
                                                          is ultimately
                                                          dependent on
                                                          the derate
                                                          factors.</span><span></span></p>
                                                      </div>
                                                    </div>
                                                    <div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal"><span
style="font-family:Verdana,sans-serif"> </span><span></span></p>
                                                      </div>
                                                    </div>
                                                    <div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal"><span
style="font-family:Verdana,sans-serif">If you can locate your subpanel
                                                          adjacent to
                                                          the main
                                                          distribution
                                                          panel, you may
                                                          be able to use
                                                          Exception #3
                                                          to
                                                          310.15(B)(2)
                                                          by connecting
                                                          the panels
                                                          with a short
                                                          nipple. I
                                                          assume you are
                                                          just looking
                                                          at a number of
                                                          conductor
                                                          derate and not
                                                          an ambient
                                                          temperature
                                                          derate.</span><span></span></p>
                                                      </div>
                                                    </div>
                                                    <div>
                                                      <p
                                                        class="MsoNormal"><span> </span></p>
                                                    </div>
                                                    <div>
                                                      <div>
                                                        <div
                                                          style="margin-bottom:6pt">
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:10pt;font-family:Verdana,sans-serif">Jason Szumlanski</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:10pt;font-family:Verdana,sans-serif">Fafco Solar</span><span></span></p>
                                                          </div>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:10pt;font-family:Verdana,sans-serif"><br>
                                                                       
                                                                       
                                                                       
                                                                </span></p>
                                                          </div>
                                                        </div>
                                                      </div>
                                                    </div>
                                                    <div>
                                                      <p
                                                        class="MsoNormal"
style="margin-bottom:12pt"><span> </span></p>
                                                      <div>
                                                        <div>
                                                          <p
                                                          class="MsoNormal"><span>On
                                                          Tue, Mar 4,
                                                          2014 at 12:05
                                                          PM, Kirk
                                                          Herander <<a
moz-do-not-send="true" href="mailto:kirk@vtsolar.com" target="_blank">kirk@vtsolar.com</a>>

                                                          wrote:</span></p>
                                                        </div>
                                                        <div>
                                                          <div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt">Hello,</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt">I have a 225 amp 3-phase main lug sub-panel
                                                          protected by a
                                                          200 amp
                                                          breaker. My
                                                          inverter
                                                          breaker
                                                          feeding the
                                                          sub panel is
                                                          60 amps. So
                                                          225 a bus x
                                                          1.2 = 270
                                                          amps. That’s
                                                          less than the
                                                          sum of the two
                                                          breakers of
                                                          260 amps, so
                                                          no issue
                                                          there. The
                                                          conductors
                                                          between sub
                                                          and main panel
                                                          have to be
                                                          rated for at
                                                          least 260/1.2
                                                          = 217 amps,
                                                          correct? Is
                                                          this 217 amps
                                                          before or
                                                          after derating
                                                          the conductor?</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt"> </span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt"> </span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt">Kirk Herander</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt">VT Solar, LLC</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt">dba Vermont Solar Engineering</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt">NABCEP<sup>TM<span> </span></sup>Certified
                                                          Inaugural
                                                          Certificant</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt">NYSERDA-eligible Installer</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt">VT RE Incentive Program Partner</span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-size:14pt"><a moz-do-not-send="true" href="tel:802.863.1202"
target="_blank">802.863.1202</a></span><span></span></p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span> </span></p>
                                                          </div>
                                                          </div>
                                                        </div>
                                                      </div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal"><span> </span></p>
                                                      </div>
                                                    </div>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"><span><br>
                                                      </span></p>
                                                  </div>
                                                </blockquote>
                                              </div>
                                            </div>
                                          </div>
                                        </div>
                                      </blockquote>
                                    </div>
                                  </blockquote>
                                </div>
                              </div>
                            </div>
                          </blockquote>
                        </div>
                      </div>
                    </blockquote>
                  </div>
                </div>
              </div>
              <br>
            </blockquote>
          </div>
          <br>
        </div>
      </div>
      <br>
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