<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif">Yeah, I assumed you meant the four conductors. The exception would solve your problem if it's physically possible.</div><div class="gmail_default" style="font-family:verdana,sans-serif">
<br></div><div class="gmail_default" style="font-family:verdana,sans-serif">How long of a run are we talking about? The cost difference shouldn't be bad for a short distance.</div><br><br><div id="WISESTAMP_SIG_gmail_session">
<div style="font-size:13px;font-family:Verdana,Arial,Helvetica,sans-serif"><div style="margin:0 0 8px 0"><p style="margin:0"><span><span>Jason Szumlansk</span></span></p><div class="gmail_default" style="font-family:verdana,sans-serif;display:inline">
i</div><p></p><p style="margin:0"><span><span></span></span></p><div class="gmail_default" style="font-family:verdana,sans-serif;display:inline">Fafco Solar</div><p></p><div style="clear:both"></div></div><img src="https://wisestamp.appspot.com/pixview.gif?p=chrome&v=3.31.0&t=1393966979650&u=ce9344a8140ce271" width="1" height="1"></div>
</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Mar 4, 2014 at 3:34 PM, Kirk Herander <span dir="ltr"><<a href="mailto:kirk@vtsolar.com" target="_blank">kirk@vtsolar.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-US" link="blue" vlink="purple"><div><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">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.<u></u><u></u></span></p>
<div class=""><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Kirk Herander<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">VT Solar, LLC<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">dba Vermont Solar Engineering<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">NABCEP<sup>TM </sup>Certified Inaugural Certificant<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">NYSERDA-eligible Installer<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d">VT RE Incentive Program Partner<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><a href="tel:802.863.1202" value="+18028631202" target="_blank">802.863.1202</a><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p></div><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a> [mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Jason Szumlanski<br>
<b>Sent:</b> Tuesday, March 04, 2014 2:57 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] conductors and the 120% rule<u></u><u></u></span></p><p class="MsoNormal"><u></u> <u></u></p><div><div class="">
<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.<u></u><u></u></span></p>
</div><div><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif""><u></u> <u></u></span></p></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.<u></u><u></u></span></p>
</div><p class="MsoNormal"><u></u> <u></u></p></div><div><div><div style="margin-bottom:6.0pt"><p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Jason Szumlanski<u></u><u></u></span></p>
<div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif"">Fafco Solar<u></u><u></u></span></p></div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><br>
<u></u><u></u></span></p></div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Verdana","sans-serif";border:solid windowtext 1.0pt;padding:0in"><img width="1" height="1" src="cid:image001.jpg@01CF37BF.3DF87CD0" alt="Description: Image removed by sender."></span><span style="font-size:10.0pt;font-family:"Verdana","sans-serif""><u></u><u></u></span></p>
</div></div><div class=""><div><p class="MsoNormal" style="margin-bottom:12.0pt"><u></u> <u></u></p><div><p class="MsoNormal">On Tue, Mar 4, 2014 at 12:05 PM, Kirk Herander <<a href="mailto:kirk@vtsolar.com" target="_blank">kirk@vtsolar.com</a>> wrote:<u></u><u></u></p>
<div><div><p class="MsoNormal"><span style="font-size:14.0pt">Hello,</span><u></u><u></u></p><p class="MsoNormal"><span style="font-size:14.0pt">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><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:14.0pt"> </span><u></u><u></u></p><p class="MsoNormal"><span style="font-size:14.0pt"> </span><u></u><u></u></p><p class="MsoNormal"><span style="font-size:14.0pt">Kirk Herander</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:14.0pt">VT Solar, LLC</span><u></u><u></u></p><p class="MsoNormal"><span style="font-size:14.0pt">dba Vermont Solar Engineering</span><u></u><u></u></p><p class="MsoNormal"><span style="font-size:14.0pt">NABCEP<sup>TM </sup>Certified Inaugural Certificant</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:14.0pt">NYSERDA-eligible Installer</span><u></u><u></u></p><p class="MsoNormal"><span style="font-size:14.0pt">VT RE Incentive Program Partner</span><u></u><u></u></p><p class="MsoNormal">
<span style="font-size:14.0pt"><a href="tel:802.863.1202" target="_blank">802.863.1202</a></span><u></u><u></u></p><p class="MsoNormal"> <u></u><u></u></p></div></div></div><p class="MsoNormal"><u></u> <u></u></p></div></div>
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