<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div dir="ltr"></div><div dir="ltr">Hi Zeke</div><div dir="ltr"><br></div><div dir="ltr">I\u2019ve never had to do RSS on a ground array because</div><div dir="ltr"><br></div><div dir="ltr">1. It\u2019s not a structure </div><div dir="ltr">2 if it is a structure then it\u2019s only being used for solar which makes it exempt from RSS. </div><div dir="ltr"><br></div><div dir="ltr">Of course your crazy AHJ might have a different opinion </div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr"><br><blockquote type="cite">On Nov 19, 2025, at 8:50\u202fAM, Zeke Yewdall via RE-wrenches <re-wrenches@lists.re-wrenches.org> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr">\ufeff<div dir="ltr"><div>You mention doing RSS on ground mounted PV arrays. This seems completely not required by the code. From my reading of 690.12, module level remote controlled rapid shutdown is only required on inhabited structures -- ones that may involve roof operations of the fire department for ventilation. Even detached garages with no occupancy do not appear to require it. If we are just talking about the conductors coming off of the array going into a home, it seems to me (and my inspectors have always agreed.. not initially, but after I discussed it with them) that a switch mounted on the groundmount array or where the underground conduit came up to go into the building would suffice.</div><div><br></div><div>Zeke</div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Tue, Nov 18, 2025 at 10:10\u202fPM 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 class="msg-4054995515141776875"><div lang="EN-US"><div class="m_-4054995515141776875WordSection1"><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)">Zeke:</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)">When this subject came up one of the wrenches replied to me off-list and shared photos of an Alps RSD that had burned up. He said tech support was of little help. </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)">Since then I have heard similar stories about Tigo products. </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)">I think the problem is trying to interrupt high voltage / high current PV DC under load. To do this with a mechanical switch you would see large blades surrounded by arc chutes, plastic shields and a metal can. Doing this switching in a small plastic nodule seems impractical.</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)">I am the last one to discount safety equipment--electrical fires kill a lot of people. However I am convinced that the RSS requirement preceded the availability equipment to implement the requirement and that gap has not closed. Now with UL3471 diluting the seriousness of hazard levels, RSS seems even more ludicrous. It is especially onerous to require module level RSS on ground mount arrays.</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)">Even more galling is the inability to complete a job I am in the middle of because there is apparently a nationwide shortage of RSDs.</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)">William</span></p><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif";color:rgb(31,73,125)"> </span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:rgb(31,73,125)">Miller Solar</span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:rgb(31,73,125)">17395 Oak Road, Atascadero, CA 93422</span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:rgb(31,73,125)">805-438-5600</span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:rgb(31,73,125)"><a href="http://www.millersolar.com/" target="_blank"><span style="color:blue">www.millersolar.com</span></a></span></p><p class="MsoNormal"><span style="font-family:"Arial","sans-serif";color:rgb(31,73,125)">CA Lic. 773985</span></p><p class="MsoNormal"><span style="font-size:11pt;font-family:"Calibri","sans-serif";color:rgb(31,73,125)"> </span></p></div></div></div></blockquote></div></div>
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