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    Mike,<br>
    Why do you make this exception, please?<br>
    <br>
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        <p class="MsoNormal" style=""><span class="il"><b style="">Allan</b></span><b
            style=""> Sindelar</b><span style="font-size: 10pt;"><br>
            <a href="mailto:Allan@positiveenergysolar.com"
              target="_blank"><span class="il">Allan</span>@positiveenergysolar.com</a><br>
            NABCEP Certified Photovoltaic Installer<br>
            EE98J Journeyman Electrician<br>
            <b style="">Positive Energy, Inc.</b><br>
            3201 Calle Marie<br>
            Santa Fe, New Mexico 87507<br>
            <b style="">505 424-1112</b><br>
            <a href="http://www.positiveenergysolar.com/"
              target="_blank">www.positiveenergysolar.com</a></span></p>
      </div>
    </div>
    <br>
    On 7/22/2010 2:12 PM, Michael Kelly wrote:
    <blockquote cite="mid:00e201cb29da$40a7a8d0$c1f6fa70$@com"
      type="cite">
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        <p class="MsoNormal"><span style="font-size: 11pt; font-family:
            "Calibri","sans-serif";">Hi
            All,<o:p></o:p></span></p>
        <p class="MsoNormal"><span style="font-size: 11pt; font-family:
            "Calibri","sans-serif";"><o:p> </o:p></span></p>
        <p class="MsoNormal"><span style="font-size: 11pt; font-family:
            "Calibri","sans-serif";">I
            agree with Ray with the exception that I use Imp*1.25 in my
            calculations. 
            I developed a simple spreadsheet for either fixed conductor
            size or for fixed
            voltage drop.  You can feel free to use it by downloading
            here: <a moz-do-not-send="true"
href="http://www.mechanicalmike.com/solar/DC_Voltage_Drop_Calculations_Template_04_20_2010.xltx">http://www.mechanicalmike.com/solar/DC_Voltage_Drop_Calculations_Template_04_20_2010.xltx</a>.<o:p></o:p></span></p>
        <p class="MsoNormal"><span style="font-size: 11pt; font-family:
            "Calibri","sans-serif";"><o:p> </o:p></span></p>
        <p class="MsoNormal"><span style="font-size: 11pt; font-family:
            "Calibri","sans-serif";">-
            Mike<o:p></o:p></span></p>
        <div>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";">---<o:p></o:p></span></p>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";">Michael
              Kelly<br>
              Applications Engineer<o:p></o:p></span></p>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";">NABCEP
Certified
              Solar PV Installer ™<o:p></o:p></span></p>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";"><img
                id="Picture_x0020_1"
                src="cid:part1.07000004.08000303@positiveenergysolar.com"
                alt="toplogo" width="150" border="0" height="36"><br>
              Solectria Renewables, LLC<o:p></o:p></span></p>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";">360
Merrimack
              St.<o:p></o:p></span></p>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";">Building
9,
              Floor 2<o:p></o:p></span></p>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";">Lawrence,
MA
              01843<br>
              Phone: 978-683-9700 ext. 167<br>
              Fax: 978-683-9702<o:p></o:p></span></p>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";"><a
                moz-do-not-send="true" href="mailto:mike@solren.com">mike@solren.com</a><o:p></o:p></span></p>
          <p class="MsoNormal"><span style="font-size: 11pt;
              font-family: "Calibri","sans-serif";"><a
                moz-do-not-send="true" href="http://www.solren.com/">www.solren.com</a><o:p></o:p></span></p>
        </div>
        <p class="MsoNormal"><span style="font-size: 11pt; font-family:
            "Calibri","sans-serif";"><o:p> </o:p></span></p>
        <div>
          <div style="border-right: medium none; border-width: 1pt
            medium medium; border-style: solid none none; border-color:
            rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color;
            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 class="moz-txt-link-abbreviated" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
                [<a class="moz-txt-link-freetext" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On
                  Behalf Of </b>R Ray
                Walters<br>
                <b>Sent:</b> Thursday, July 22, 2010 3:45 PM<br>
                <b>To:</b> RE-wrenches<br>
                <b>Subject:</b> Re: [RE-wrenches] calculating DC voltage
                drop<o:p></o:p></span></p>
          </div>
        </div>
        <p class="MsoNormal"><o:p> </o:p></p>
        <p class="MsoNormal">I use actual operating current, without
          multipliers. I also
          use actual temperatures, not the worst case temperatures that
          many use.<o:p></o:p></p>
        <div>
          <p class="MsoNormal">I created a spread sheet that uses the
            NEC adjustments for
            wire temperature, (see NEC chapter 9, table 8, FPN 2)<o:p></o:p></p>
        </div>
        <div>
          <p class="MsoNormal">It makes quite a difference!<o:p></o:p></p>
          <div>
            <p class="MsoNormal">Volt drop and the accompanying loss of
              energy production
              needs to be looked at realistically under normal operating
              conditions. Adding
              worst case multipliers is necessary for sizing cables and
              breakers for safety,
              but it isn't appropriate when calculating energy losses.
              We shouldn't do an
              energy loss analysis for a situation that might never
              occur, or for only a very
              small % of the time. <o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal">A correct analysis will reflect actual
              losses over the
              lifetime of the system, so that an informed economic
              decision can be made.
              Especially on larger systems with long runs, its worth it
              to you and the client
              to use real world numbers, not blind over sizing.<o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal">I got into this over a decade ago, when
              I noticed that
              actual measured volt drop was much less than calculated,
              now my calculations
              match real measurements. <o:p></o:p></p>
          </div>
          <div>
            <p class="MsoNormal"><o:p> </o:p></p>
            <div>
              <div>
                <p class="MsoNormal"><span style="font-size: 9pt;
                    font-family:
                    "Helvetica","sans-serif"; color:
                    black;">R. Walters<o:p></o:p></span></p>
              </div>
              <div>
                <p class="MsoNormal"><span style="font-size: 9pt;
                    font-family:
                    "Helvetica","sans-serif"; color:
                    black;"><a moz-do-not-send="true"
                      href="mailto:ray@solarray.com">ray@solarray.com</a><o:p></o:p></span></p>
              </div>
              <div>
                <p class="MsoNormal"><span style="font-size: 9pt;
                    font-family:
                    "Helvetica","sans-serif"; color:
                    black;">Solar Engineer<o:p></o:p></span></p>
              </div>
              <div>
                <p class="MsoNormal"><span style="font-size: 9pt;
                    font-family:
                    "Helvetica","sans-serif"; color:
                    black;"><o:p> </o:p></span></p>
              </div>
              <div>
                <p class="MsoNormal"><span style="font-size: 9pt;
                    font-family:
                    "Helvetica","sans-serif"; color:
                    black;"><o:p> </o:p></span></p>
              </div>
              <p class="MsoNormal"><span style="font-size: 9pt;
                  font-family:
                  "Helvetica","sans-serif"; color:
                  black;"><br>
                  <br>
                </span><o:p></o:p></p>
            </div>
            <p class="MsoNormal"><o:p> </o:p></p>
            <div>
              <div>
                <p class="MsoNormal">On Jul 22, 2010, at 1:22 PM, Marco
                  Mangelsdorf wrote:<o:p></o:p></p>
              </div>
              <p class="MsoNormal"><br>
                <br>
                <o:p></o:p></p>
              <div>
                <div>
                  <p class="MsoNormal"><span style="font-size: 11pt;
                      font-family:
                      "Calibri","sans-serif";">When
                      calculating the voltage drop from a PV array to
                      the inverter, what’s the
                      most common accepted practice?  To use the Isc X
                      1.25 or 1.56 as the
                      multiplier?<o:p></o:p></span></p>
                </div>
                <div>
                  <p class="MsoNormal"><span style="font-size: 11pt;
                      font-family:
                      "Calibri","sans-serif";"> <o:p></o:p></span></p>
                </div>
                <div>
                  <p class="MsoNormal"><span style="font-size: 11pt;
                      font-family:
                      "Calibri","sans-serif";">Thanks,<o:p></o:p></span></p>
                </div>
                <div>
                  <p class="MsoNormal"><span style="font-size: 11pt;
                      font-family:
                      "Calibri","sans-serif";">marco<o:p></o:p></span></p>
                </div>
                <div>
                  <p class="MsoNormal"><span style="font-size: 11pt;
                      font-family:
                      "Calibri","sans-serif";"> <o:p></o:p></span></p>
                </div>
                <p class="MsoNormal" style="margin-bottom: 13.5pt;"><span
                    style="font-size: 13.5pt; font-family:
                    "Helvetica","sans-serif";">_______________________________________________<br>
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            <p class="MsoNormal"><o:p> </o:p></p>
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      <pre wrap="">
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List rules & etiquette:
<a class="moz-txt-link-abbreviated" href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a>

Check out participant bios:
<a class="moz-txt-link-abbreviated" href="http://www.members.re-wrenches.org">www.members.re-wrenches.org</a>

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