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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="color:#1f497d">This topic came up on the list previously. Since isolated transformer based inverters are going the way of the dodo, the only reasonable inverter upgrade choice is to replace old inverters with new transformerless models. As was previously pointed out here, these modern inverters have much more robust ground fault and arc fault detection capabilities, so they’re safer anyway. We just phase tape up the previously grounded white DC conductor(s), make sure the positive and negatives on the DC side are switched, and call it a day. I realize that some of the NEC technicalities are being bent here, but this solution is the lesser of evils.</span></p><p class="MsoNormal"><span style="color:#1f497d"> </span></p><p class="MsoNormal"><span style="color:#1f497d">August</span></p><p class="MsoNormal"><span style="color:#1f497d"> </span></p><p class="MsoNormal"><span style="color:#1f497d"> </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"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> RE-wrenches [mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Glenn Burt<br><b>Sent:</b> Friday, July 22, 2016 5:08 AM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Replacing grounded inverters</span></p></div></div><p class="MsoNormal"> </p><div><div><p class="MsoNormal">If you read some of the proposed changes for the 2017 NEC, it is looking life there will be no problem replacing isolated inverters with non-isolated versions. In fact the proposed wording seems to allow either USE, or PV wire to be used with non-isolated inverters explicitly going forward.<br>It made me feel better about doing recent replacements.<br>I'm having more trouble with the TL inverters and AFCI issues on older systems, however.</p></div></div><div><div class="MsoNormal" align="center" style="text-align:center"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><hr size="2" width="100%" align="center"></span></div><p class="MsoNormal" style="margin-bottom:12.0pt"><b>From: </b><a href="mailto:Gary@SYVSolar.com">Gary at Santa Ynez Valley Solar</a><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br></span><b>Sent: </b>7/21/2016 21:43<span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br></span><b>To: </b><a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br></span><b>Subject: </b>[RE-wrenches] Replacing grounded inverters<span style="font-size:12.0pt;font-family:"Times New Roman","serif""></span></p></div><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black">We are all facing having to replace the old transformer based inverters when they run out. Really difficult to find replacements. Against code to replace with transformer less ones. I wonder if a DC/DC transformer could be installed just ahead of the transformer less inverter for isolation purposes? Not clear on the concept.</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black">Gary</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black">Gary Gordon</span></p><p class="MsoNormal"><span style="font-size:4.0pt;font-family:"Gotham Book";color:black"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> <img border="0" width="115" height="39" id="Picture_x0020_1" src="cid:image001.jpg@01D1E37E.6CF62470" alt="cid:image001.jpg@01D06621.23813A90"></span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> </span><span style="color:black"><a href="http://www.syvsolar.com/"><span style="font-size:10.0pt;font-family:"Gotham Book"">www.SYVSolar.com</span></a></span><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"></span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> PO Box 688 </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> Santa Ynez, CA 93460</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> 805 688-1213</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> NABCEP Certified Installer</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Gotham Book";color:black"> CA Licensed Solar Contractor</span></p><p class="MsoNormal"> </p></div></body></html>