<html><head></head><body><div style="color:#000; background-color:#fff; font-family:verdana, helvetica, sans-serif;font-size:16px"><div id="yui_3_16_0_ym19_1_1523444138610_92590">Hi Aaron--</div><div id="yui_3_16_0_ym19_1_1523444138610_92591"><br></div><div id="yui_3_16_0_ym19_1_1523444138610_92592">In high strength concrete, we've used red head trubolt wedge anchors, with 1/2" plate (6x6), four anchors/plate, with the posts welded to the plate. This setup passed engineering muster. The anchors were 3/4" by 4-3/4".</div><div id="yui_3_16_0_ym19_1_1523444138610_92682"><br></div><div id="yui_3_16_0_ym19_1_1523444138610_92809">The racking posts were a tripod of 4x6 stock welded to a pipe that would tilt the racking. A few years later, 90 mph winds sheared the pins that pinned the racking to the post assembly. A few cracked modules, but the wedge anchors held just fine. <br></div><div id="yui_3_16_0_ym19_1_1523444138610_92852"><br></div><div id="yui_3_16_0_ym19_1_1523444138610_92909" dir="ltr">We've used a Bosch spline drive drill over the years (<span id="yui_3_16_0_ym19_1_1523444138610_93051">11265EVS, about $600) and have been pleased with it. You can rent it or its big Makita cousin (HR5000) since your drilling down. The hammer drills are also sold in a sds version, but I've been old school. If you're not doing a lot of concrete rock work, I'd suggest buy a new bit and rent the drill. SDS bits cost a little less than splines and the 3/4" prices range from $25 to $50. <br></span></div><div id="yui_3_16_0_ym19_1_1523444138610_92697"><span></span></div><div id="yui_3_16_0_ym19_1_1523444138610_92929"> </div><div class="signature" id="yui_3_16_0_ym19_1_1523444138610_92928"><div id="yui_3_16_0_ym19_1_1523444138610_92927">Bill Hennessy<br>Berks Solar, LLC<br>371 Centennial Rd<br>Mertztown, PA 19539<br><br>o 610 682 4300<br>c 484 560 4666<br>NABCEP certified installer<br>PA contractor #44411<br>www.berkssolar.com</div></div><div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_ym19_1_1523444138610_93454" style="display: block;"> <div style="font-family: verdana, helvetica, sans-serif; font-size: 16px;" id="yui_3_16_0_ym19_1_1523444138610_93453"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_ym19_1_1523444138610_93452"> <div dir="ltr" id="yui_3_16_0_ym19_1_1523444138610_93451"> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Aaron Mandelkorn <reosolar@gmail.com><br> <b><span style="font-weight: bold;">To:</span></b> RE-wrenches <re-wrenches@lists.re-wrenches.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Thursday, April 12, 2018 9:28 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> [RE-wrenches] Mounting on rock<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_ym19_1_1523444138610_93457"><br><div id="yiv3812534551"><div id="yui_3_16_0_ym19_1_1523444138610_93456">Hi all,<div id="yui_3_16_0_ym19_1_1523444138610_93473"><br></div><div id="yui_3_16_0_ym19_1_1523444138610_93458">I have a customer that requires a mounting option I have yet to encounter. His site sits on top of of a massive hill of granite. It is relatively flat. Are there any mounting options that could work here? We are only talking about (12) to (16) modules for an off grid array. Is there anything that can bolt to rock? I typically use dpw or Mt solar pole mounts but can't imagine how these options could work. Any thoughts? <br><br><div id="yui_3_16_0_ym19_1_1523444138610_93474">Aaron Mandelkorn<br>President / Founder<br>Renewable Energy Outfitters<br><a rel="nofollow" target="_blank" href="http://www.reosolar.com/">www.reosolar.com</a><br>Off Grid Depot<br><a rel="nofollow" target="_blank" href="http://www.offgridnow.com/">www.offgridnow.com</a><br>970-596-3744<br><br> </div></div></div></div>_______________________________________________<br>List sponsored by Redwood Alliance<br><br>List Address: <a ymailto="mailto:RE-wrenches@lists.re-wrenches.org" href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br><br>Change listserver email address & settings:<br><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target="_blank">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><br><br>List-Archive: <a href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html" target="_blank">http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html</a><br><br>List rules & etiquette:<br>www.re-wrenches.org/etiquette.htm<br><br>Check out or update participant bios:<br>www.members.re-wrenches.org<br><br><br><br></div> </div> </div> </div></div></body></html>