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--></style></head><body lang="EN-US" link="blue" vlink="purple" style="word-wrap:break-word"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">Lloyd:</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">Thank you for your reply. That is how I read the instructions for all of the aforementioned MLPE devices.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">I think there is a flaw in the logic here, at least for the NEP and Tigo products. It is because both manufacturers offer rail or frame mounting options. This is significant for this reason:</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">If you are frame-mounting an MLPE device it is convenient to connect PV leads to the MLPE first and you can easily comply with the instructions.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">If, however, you are rail-mounting the MLPE it is quite inconvenient to not be allowed to interconnect the MLPE devices before connecting the PV. You really need to complete all of the hardware and wiring infrastructure associate with your mounting system before you bring your modules to the roof. It is very awkward to be juggling a panel on the roof to connect it to rail-mounted MLPE before you are allowed to interconnect the rail-mounted MLPE devices. </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">It is my opinion that if your MLPE devices cannot be interconnected, you should not offer a rail-mount option. </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">It is important that we use proper terminology for these parts of the system. “Interconnecting” and “home-runs” are different things: Interconnecting leads are between devices. Home-runs are leads run between the ends of strings of devices and the terminating equipment. NEP equated these in their quick start guide and this caused confusion.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">I spoke to George with NEP today about this. I presented this dilemma and he seemed to understand the conflict. George told me the concern is that if an installer connected a PV panel to the series-string output of the PVG units, damage to the MLPE unit could occur. They do have the same MC4 connectors so this is possible.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">I get the concept that even the dumbest mistakes are possible, but it would be hard to confuse the different connections. The PV inputs are quite short and the series-string connections are abundantly long. Also they are clearly labeled. George told me that as long as the home-runs were left unterminated, the interconnecting leads can be connected prior to connecting PV without risking damage to the PVG units.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">As always, the devil is in the details. Success is achieved in understanding and dealing with the details.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d">William Miller</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";color:#1f497d"> </span></p><div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif";color:#1f497d">Miller Solar</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif";color:#1f497d">17395 Oak Road, Atascadero, CA 93422</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif";color:#1f497d">805-438-5600</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif";color:#1f497d"><a href="http://www.millersolar.com/"><span style="color:blue">www.millersolar.com</span></a></span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif";color:#1f497d">CA Lic. 773985</span></p><p class="MsoNormal"><span style="color:#1f497d"> </span></p></div><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif";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""> Lloyd Hoffstatter [mailto:<a href="mailto:lloyd@sunstruckconsulting.com">lloyd@sunstruckconsulting.com</a>] <br><b>Sent:</b> Tuesday, November 12, 2024 7:44 AM<br><b>To:</b> <a href="mailto:william@millersolar.com">william@millersolar.com</a>; RE-wrenches<br><b>Subject:</b> RE: [RE-wrenches] NEP PVG wiring</span></p></div></div><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-family:Aptos">Hi William,</span></p><p class="MsoNormal"><span style="font-family:Aptos"> </span></p><p class="MsoNormal"><span style="font-family:Aptos">The RSD installation instructions mirror those of TIGO and APSmart per connection order of PV to RSD first.</span></p><p class="MsoNormal"><span style="font-family:Aptos"> </span></p><p class="MsoNormal"><span style="font-family:Aptos">Best regards,</span></p><p class="MsoNormal"><span style="font-family:Aptos">Lloyd</span></p><p class="MsoNormal"><span style="font-family:Aptos"> </span></p><div><p class="MsoNormal">Lloyd Hoffstatter, M.S. Applied Solar Energy</p><p class="MsoNormal">Director, Sunstruck Consulting</p><p class="MsoNormal"><u><span style="color:#0563c1"><a href="mailto:lloyd@sunstruckconsulting.com"><span style="color:#0563c1">lloyd@sunstruckconsulting.com</span></a></span></u></p><p class="MsoNormal">845-657-8132 (office)</p><p class="MsoNormal">914-844-3404 (cell)</p></div><p class="MsoNormal"> <span style="font-family:Aptos"></span></p><div><div style="border:none;border-top:solid #e1e1e1 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b>From:</b> RE-wrenches <<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>> <b>On Behalf Of </b>William Miller via RE-wrenches<br><b>Sent:</b> Monday, November 11, 2024 11:30 PM<br><b>To:</b> RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br><b>Cc:</b> William Miller <<a href="mailto:william@millersolar.com">william@millersolar.com</a>><br><b>Subject:</b> [RE-wrenches] NEP PVG wiring</p></div></div><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Friends:</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">I am repairing a site with NEP PVG RSD devices. We will be removing all of the modules and finding out why the system is underperforming and why 2 of the units are not reporting.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="Default"><span style="font-family:"Verdana","sans-serif"">The quick start guide includes this line: </span><span style="font-size:16.0pt">PVG’s PV-lead pairs must be connected to PV modules before connecting homerun cables between RSD device.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">I find this wording confusing. Homerun cables do not connect between RSD devices, home runs connect to the PV input on an inverter (Soul-Arc in this case).</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">I wish to rail mount the PVG RSD devices, connect the series wiring between these modules and then connect the PV. Can I interconnect the PVG units prior to connecting the PV modules? This sure would make the process easier.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Thanks in advance for in any input on working with these units.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">William Miller</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">Miller Solar</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">17395 Oak Road, Atascadero, CA 93422</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">805-438-5600</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif""><a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__www.millersolar.com_&d=DwMFaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=p2tHyHEAjVe2zSh4C_236V4KkHnn0z0ynUvWz0mobds&m=Sj6SvGiGAeDHb1dV0napuS0qhQ9nlBiveGTpGaibMKwEylmjU3_fIw0-VKruQ-jo&s=DC5TfZLJCY1FTLE0G9RSxAQIvPgwzSR54I9_gSu5gJM&e=">www.millersolar.com</a></span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">CA Lic. 773985</span></p><p class="MsoNormal"> </p><p class="MsoNormal"> </p></div></body></html>