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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Thanks Allen for clarifying why a 60A is required. I was wondering. The spec does list a surge current of 9000W so I thought that may be the rationale, but even that would only require a 50A, and since this surge occurs during ‘stand-alone mode’ it didn’t seem to apply to the OCPD at the main panel. Your explanation makes more sense, but I wonder why then they don’t list the AC input breaker size as 60A <i>max</i>. If you have few backup loads, and are not on the 2011 NEC, a 40A could theoretically be fine?<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Thanks all for your thoughts, much appreciated.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Garrison<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Allan Sindelar<br><b>Sent:</b> Wednesday, February 27, 2013 6:08 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Conductor Sizing for Supply Side Connection<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal style='margin-bottom:12.0pt'>August,<br>The 60A breaker is intended to allow grid power to pass through to the loads in excess of the inverter's stand-alone output. The point of 705.12 (moved in the 2011 NEC from 690.64 (B)(2)) is to differentiate between load pass-through current and sell current. The amount of current fed into the grid is (4500/230 =) 19.56A, while the amount that can be taken from the grid and passed through to the load is much greater. If you were limited to a 40A breaker in order to maintain 120% of a 200A main bus, you'd be prone to nuisance trips under large cumulative loads.<br><br>Allan<o:p></o:p></p><div><p class=MsoNormal><b>Allan Sindelar</b><br><span style='font-size:10.0pt'><a href="mailto:Allan@positiveenergysolar.com"><span style='color:#000099'>Allan@positiveenergysolar.com</span></a></span><br><span style='font-size:10.0pt'>NABCEP Certified Photovoltaic Installer<br>NABCEP Certified Technical Sales Professional<br>New Mexico EE98J Journeyman Electrician<br>Founder and Chief Technology Officer<br><b>Positive Energy, Inc.</b><br>3209 Richards Lane (note new address)<br>Santa Fe, New Mexico 87507<br><b>505 424-1112</b><br><a href="http://www.positiveenergysolar.com/" target="_blank">www.positiveenergysolar.com</a></span> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;margin-right:722.25pt;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p></div></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><pre><o:p> </o:p></pre></blockquote><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p></div></body></html>