<div dir="ltr">I agree with Mike on this, as written this is a bad Section, and in reality there is no need for it, so deleting it is better than trying to fix something that is unnecessary.<div><br></div><div>The 2014 690.7(D) language has changed - the title is now "Additional Auxiliary Electrodes.."; in 2008 the title to be "Additional Electrodes...". It can be confusing to keep the terminology straight, but:</div>
<div><br></div><div><ul><li>"Additional Electrodes" from 2008 is seemingly undefined, <br></li><li>"Supplemental Electrodes" may be required as part of the grounding electrode system per 250.53(A)(2) and (3)<br>
</li><li>Auxiliary electrodes are defined in 250.54<br></li></ul></div><div><br></div><div>It's the allowances for Auxiliary Electrodes which cause the problem. 250.54, which must be followed per 690.47(D), states that auxiliary electrodes do not have to be bonded to the grounded electrode system (as is typically required of all present electrodes per 250.50), nor does it have to follow the bonding jumper sizing requirements of 250.53(C).</div>
<div><br></div><div>This creates the problem Mike describes - two connections to ground that can have dramatically different potential between them in the event of a lightning incident. </div><div><br></div><div>I've always been a proponent of bonding residential pole and ground-mounted PV structures back to the grounding system of the building they serve. Large ground-mounted solar farms have lot of auxiliary/supplemental/additional electrodes in the form of pilings, and the systems I work on have these all bonded together and back to the electrodes at the inverter pads - it's extra copper in the ground but it helps alleviate the problem of different potentials.</div>
<div><br></div><div>The problem is for roof-mounted systems; the 2008 language, by not explicitly calling it an auxiliary electrode, basically meant that inspectors were requiring the additional electrode to be bonded to the existing grounding electrode system on the building - which alleviates the concerns of having two connections to the Earth. Now 2014 calls it "Auxiliary" and the language in 250 specifically says it doesn't have to be bonded to the grounding electrode system - enter the safety concerns described by Mike and Bill. </div>
<div><br></div><div>Not having to bond the 690.47(D) Auxiliary electrode to the grounding electrode system alleviates some of the pain of having to put that rod in, so I imagine that many installers will take this route if the AHJ allows it. Thus the need to do something about this, before it lingers for years and years. So...go Bill!</div>
<div><br></div><div><br></div><div><br></div></div><div class="gmail_extra"><br clear="all"><div><div dir="ltr"><div><br></div><div>Brian Mehalic <br>NABCEP Certified Solar PV Installation Professional™ R031508-59<div>IREC ISPQ Certified Affiliated Instructor/PV US-0132<br>
<div><br></div><div>PV Curriculum Developer and Instructor<div>Solar Energy International<br><a href="http://www.solarenergy.org" target="_blank">http://www.solarenergy.org</a></div></div></div></div></div></div>
<br><br><div class="gmail_quote">On Mon, Dec 9, 2013 at 3:50 PM, Glenn Burt <span dir="ltr"><<a href="mailto:glenn.burt@glbcc.com" target="_blank">glenn.burt@glbcc.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="EN-US" link="blue" vlink="purple"><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">The bad news from the 2014 codebook:<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Times-Bold","serif"">690.47 Grounding Electrode System.</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:10.0pt;font-family:"Times-Bold","serif"">(D) Additional Auxiliary Electrodes for Array Grounding.<u></u><u></u></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">A grounding electrode shall be installed in accordance<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none">
<span style="font-size:10.0pt;font-family:"Times-Roman","serif"">with 250.52 and 250.54 at the location of all ground- and<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">pole-mounted PV arrays and as close as practicable to the<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">location of roof-mounted PV arrays. The electrodes shall be<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none">
<span style="font-size:10.0pt;font-family:"Times-Roman","serif"">connected directly to the array frame(s) or structure. The dc<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">grounding electrode conductor shall be sized according to<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">250.166. Additional electrodes are not permitted to be used<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none">
<span style="font-size:10.0pt;font-family:"Times-Roman","serif"">as a substitute for equipment bonding or equipment grounding<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">conductor requirements. The structure of a ground- or<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">pole-mounted PV array shall be permitted to be considered<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none">
<span style="font-size:10.0pt;font-family:"Times-Roman","serif"">a grounding electrode if it meets the requirements of<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">250.52. Roof-mounted PV arrays shall be permitted to use <u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">the metal frame of a building or structure if the requirements<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Times-Roman","serif"">of 250.52(A)(2) are met.<u></u><u></u></span></p><p class="MsoNormal" style="text-autospace:none">
<i><span style="font-size:10.0pt;font-family:"Times-Italic","serif"">Exception No. 1: An array grounding electrode(s) shall<u></u><u></u></span></i></p><p class="MsoNormal" style="text-autospace:none">
<i><span style="font-size:10.0pt;font-family:"Times-Italic","serif"">not be required where the load served by the array is integral<u></u><u></u></span></i></p><p class="MsoNormal" style="text-autospace:none">
<i><span style="font-size:10.0pt;font-family:"Times-Italic","serif"">with the array.<u></u><u></u></span></i></p><p class="MsoNormal" style="text-autospace:none"><i><span style="font-size:10.0pt;font-family:"Times-Italic","serif"">Exception No. 2: An additional array grounding electrode(<u></u><u></u></span></i></p>
<p class="MsoNormal" style="text-autospace:none"><i><span style="font-size:10.0pt;font-family:"Times-Italic","serif"">s) shall not be required if located within 1.8 m (6 ft)<u></u><u></u></span></i></p>
<p class="MsoNormal" style="text-autospace:none"><i><span style="font-size:10.0pt;font-family:"Times-Italic","serif"">of the premises wiring electrode.<u></u><u></u></span></i></p><p class="MsoNormal">
<span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">-Glenn<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<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""> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a> [mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Jason Szumlanski<br>
<b>Sent:</b> Monday, December 09, 2013 2:22 PM<br><b>To:</b> RE-wrenches</span></p><div class="im"><br><b>Subject:</b> Re: [RE-wrenches] Mike Holt Solar Video - LIVE in your town, limited time only<u></u><u></u></div><p></p>
</div><p class="MsoNormal"><u></u> <u></u></p><div><div><div><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif"">I had to quit watching at noon, so I was disappointed to have missed the theatrics. I just installed a system on my home to NEC 2008 as is followed here. I have convinced a local plans reviewer that since it was removed in NEC 2011, the building official should waive the 690.47(D) requirement for rooftop systems. He specifically asked me if it would return in NEC 2014, and if I am reading this right, the answer is definitely "no."<u></u><u></u></span></p>
</div><div><div class="h5"><div><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif""><u></u> <u></u></span></p></div><div><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif"">Since there was no aesthetically acceptable way to run the additional GEC in my case and make it "as close as practicable (which is ambiguous anyway), I cut it out immediately following inspection - something I would NEVER recommend a customer do, of course. Nonetheless, I feel this was a reasonable and acceptable move given that there are thousands of systems out there inspected under NEC 2011 that have not additional grounding electrode.<u></u><u></u></span></p>
</div><div><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif""><u></u> <u></u></span></p></div><div><p class="MsoNormal"><span style="font-family:"Verdana","sans-serif"">I will continue to listen with great interest...<u></u><u></u></span></p>
</div><p class="MsoNormal"><u></u> <u></u></p><div><div><div style="margin-bottom:4.8pt"><p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:8.0pt;font-family:"Verdana","sans-serif"">Jason Szumlanski<u></u><u></u></span></p>
<div><p class="MsoNormal"><span style="font-size:8.0pt;font-family:"Verdana","sans-serif"">Fafco Solar<u></u><u></u></span></p></div><p class="MsoNormal"><span style="font-size:8.0pt;font-family:"Verdana","sans-serif""><br>
<u></u><u></u></span></p></div><p class="MsoNormal"><span style="font-size:8.0pt;font-family:"Verdana","sans-serif""><img width="1" height="1"><u></u><u></u></span></p></div></div><p class="MsoNormal" style="margin-bottom:12.0pt">
<u></u> <u></u></p><div><p class="MsoNormal">On Mon, Dec 9, 2013 at 9:21 AM, Richard L Ratico <<a href="mailto:Richard.L.Ratico@valley.net" target="_blank">Richard.L.Ratico@valley.net</a>> wrote:<u></u><u></u></p><p class="MsoNormal">
<br>Mr. Holt explicitly stated his desire to create a groundswell of opinion to<br>immediately eliminate this requirement of the code. Would it not be better to<br>carefully think through and discuss the issue, in contrast to what was permitted<br>
on his "show"?<u></u><u></u></p></div><p class="MsoNormal" style="margin-bottom:12.0pt"><u></u> <u></u></p></div></div></div><p class="MsoNormal"><u></u> <u></u></p></div></div></div><br>_______________________________________________<br>
List sponsored by Home Power magazine<br>
<br>
List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br>
<br>
Change 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://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org" target="_blank">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br>
<br>
List rules & etiquette:<br>
<a href="http://www.re-wrenches.org/etiquette.htm" target="_blank">www.re-wrenches.org/etiquette.htm</a><br>
<br>
Check out participant bios:<br>
<a href="http://www.members.re-wrenches.org" target="_blank">www.members.re-wrenches.org</a><br>
<br>
<br></blockquote></div><br></div>