<div dir="ltr">Hi William - I think this article by Bill Brooks directly answers both of your questions:<div><br></div><div><a href="https://www.southportland.org/files/8814/8156/0204/NEC_2017_Updates_for_PV_Systems___SolarPro_Magazine.pdf">https://www.southportland.org/files/8814/8156/0204/NEC_2017_Updates_for_PV_Systems___SolarPro_Magazine.pdf</a></div><div><br></div><div>-August<br><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Sep 16, 2021 at 9:19 AM William Miller <<a href="mailto:william@millersolar.com">william@millersolar.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div lang="EN-US"><div class="gmail-m_-7657928947983819975WordSection1"><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif">Friends:</span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif"> </span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif">Thanks to all of you for your valuable input on the repowering project I am researching. I am learning a lot in the process and generating more questions as I proceed. Here is are questions that came up, and if any of you have insight, I would love to hear it:</span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif"> </span></p><p class="gmail-m_-7657928947983819975MsoListParagraph" style="margin-left:0.75in"><span style="font-size:12pt;font-family:Verdana,sans-serif"><span>1.<span style="font:7pt "Times New Roman""> </span></span></span><span style="font-size:12pt;font-family:Verdana,sans-serif">Array OCPD/disconnecting. The existing array has fuses in the positive leads only. If we were to upgrade to transformerless inverters, will we be required to install OCPD in the negative leads as well? (In researching this I came upon this entry in 2017 NEC 690.9: <i>Informational Note: Due to improved ground-fault protection required in PV systems by 690.41(B), a single overcurrent protective device in either the positive or negative conductors of a PV system in combination with this ground-fault protection provides adequate overcurrent protection.</i>)</span></p><p class="gmail-m_-7657928947983819975MsoListParagraph" style="margin-left:0.75in"><i><span style="font-size:12pt;font-family:Verdana,sans-serif"><span>2.<span style="font:7pt "Times New Roman""> </span></span></span></i><span style="font-size:12pt;font-family:Verdana,sans-serif">In the 2014 NEC when installing Ungrounded PV systems, the following requirement appeared in 690.35: <i>Conductors listed and identified as PV wire installed as exposed, single conductors\u2026</i> What happened to 690.35, and can I now use USE-2 on transformerless inverter installations?<i></i></span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif"> </span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif">Thanks in advance.</span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif"> </span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif">William Miller</span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Verdana,sans-serif"> </span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Arial,sans-serif">Miller Solar</span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Arial,sans-serif">17395 Oak Road, Atascadero, CA 93422</span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Arial,sans-serif">805-438-5600</span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Arial,sans-serif"><a href="http://www.millersolar.com/" target="_blank">www.millersolar.com</a></span></p><p class="MsoNormal"><span style="font-size:12pt;font-family:Arial,sans-serif">CA Lic. 773985</span></p><p class="MsoNormal"> </p><p class="MsoNormal"> </p></div></div>
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