<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi James,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Breakers/fuses/disconnects/load centers have an Ampere Interrupt Current (AIC) rating as well as voltage and rated trip current. This tells how much of an arc might be created during a fault or de-energization under full load.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>When selecting an overcurrent protection device at the point of utility backfeed, you should determine the available fault current to be interrupted.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The utility should be able to provide this value for you to use. We typically locate the AIC value of existing service equipment (often located on a label inside a load center or disconnect), and use this as our minimum value.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>-Glenn<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><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"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>James Rudolph<br><b>Sent:</b> Monday, October 03, 2011 1:54 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> [RE-wrenches] interrupting current calculations used to determine the interrupting of the AC equipment.<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>Dearest Wenches,<br><br> I received an e-mail from PE reviewing one of our projects to build, and this is what they wrote-<br><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:black'><br>No interrupting current calculations were included. It is suggested the utility company be consulted for available at the service entrance and these values be used to determine the interrupting of the AC equipment.</span><br><br>Does any one out there have experience dealing with this issue, or have the ability to shed some light on this subject.<br><br>Many thanks in advance,<br clear=all><br>-- <br><b>James B Rudolph<br>NABCEP Certified PV Installer<br><br></b><o:p></o:p></p></div></body></html>