Wrenches:
I think the trick is to remove the roofing from the category of “likely to become energized.” If your wire management is such that there is no way that any PV wire can come into contact with the metal roofing, then you are not obligated under 250.4(A)4 to bond. How one accomplishes this relies on one’s own ingenuity, seeing as how the industry is way behind on developing wire management hardware. I do not believe ties and clips are adequate. Instead some form of raceway is required. We love Snap-n-rack racking because the channel is deep enough to accept PV wire and Gen4 MC connectors and has snap-on covers available. The racking is your raceway and contains PV wire absolutely. You of course need to bond the racking and module frames, all of which is accomplished using the SnR hardware. We mount transition boxes near enough to the end of a string that the factory module wire connects directly to the box without extensions required. We order MC connectors as bulkhead mounts and then drill and tap Schedule 80 plugs to accept the MC connector threads. If you invite an inspector to look under your array and nary a hint of PV wire can be seen, you can make the case that the roofing is not likely to become energized. William Miller [image: Gradient Cap_mini] Lic 773985 millersolar.com <http://www.millersolar.com/> 805-438-5600 *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Glenn Burt *Sent:* Monday, June 18, 2018 11:28 AM *To:* 'RE-wrenches'; 'AE Solar' *Subject:* Re: [RE-wrenches] grounding on metal roofs NEC 250.4(A)4 Also states that normally non-current-carrying electrically conductive materials that are likely to become energized shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path. So the logic goes if an array develops a ground fault, and the faulted conductor contacts a metal roof surface, there is a possibility that the roof may become energized. So for many reasons, bond the roof to ground. -Glenn Renewable Energy Engineer – Cadmus Principal Engineer – Power Guru Principal – glb, Consulting Company *From:* RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> *On Behalf Of *br...@willpowerelect.com *Sent:* Monday, June 18, 2018 1:42 PM *To:* RE-wrenches <re-wrenches@lists.re-wrenches.org>; AE Solar < autonomousenerg...@gmail.com> *Subject:* Re: [RE-wrenches] grounding on metal roofs NEC 690.47 (A) requires the array to be grounded, not necessarily the roof. If you have bonded the rails and modules and your grounding conductor goes back to the service you should be good. 690.47 (B) allows installation of an auxiliary grounding electrode (ground rod or building steel). Not a bad idea in lightning prone areas. ;) Local AHJ may have different opinions. Bruce Fiero-RMI *"Energizing the Rogue Valley"* *4115 S Pacific Hwy* *Medford, OR 97501* *P:* 541.535.3965 *F:* 541.512.0061 *E:* br...@willpowerelect.com *W:* Willpower Electric, LLC <http://www.willpower-electric.com> *CCB **191852* *Oregon Electrical Contractor **C681* *NABCEP Certified Solar (PV) Installer **031409-38* *DUNS* *191470363* *Energy Trust of Oregon Trade Ally **Solar (PV) Installation & Energy Efficient Commercial Lighting Programs * ***This email may contain information that is privileged, confidential, or otherwise exempt from disclosure under applicable law. If you are not the addressee, or if it appears that you have received this email in error, please advise me immediately by reply email, keep the contents confidential, and immediately delete the message and any attachments from your system. * -------- Original Message -------- Subject: Re: [RE-wrenches] grounding on metal roofs From: "glenn.b...@glbcc.com" <glenn.b...@glbcc.com> Date: Sun, June 17, 2018 6:17 pm To: AE Solar <autonomousenerg...@gmail.com> Cc: RE-wrenches <re-wrenches@lists.re-wrenches.org> Depends on the seam profile. Same device may be used in many cases. We have Also drilled and used the standard direct burial lugs on the underside of the pans, at the wave when they hang over enough to get working space. Then a horizontal run of copper wire to connect. Don't be lulled into thinking that S-5 clamps are listed for grounding roof pans - they are not. They are only listed for module bonding to ground. Sent from my 'smart' phone so please excuse spelling and typos. ------ Original message------ *From: *AE Solar *Date: *Sun, Jun 17, 2018 8:46 PM *To: glenn.b...@glbcc.com <glenn.b...@glbcc.com>;* *Cc: RE-wrenches;* *Subject:Re: [RE-wrenches] grounding on metal roofs* *thanks glenn. and what about commercial? anyone have code references regarding grounding when doing solar on metal roofs? i thought a few years back there was a conversation on this but i can't seem to find it.* *Adam KatzmanAutonomous EnergiesPO Box 1245* *Kingston, NY 12402www.autonomousenergies.com <http://www.autonomousenergies.com>(518) 567-1468 <(518)%20567-1468>* *On Sun, Jun 17, 2018 at 1:46 PM, glenn.b...@glbcc.com <glenn.b...@glbcc.com> <glenn.b...@glbcc.com <glenn.b...@glbcc.com>> wrote:* *We use the Ilsco SGB-4 ground lug on every pan under the array for residential systems.* *-Glenn* *Sent from my Verizon LG Smartphone* *------ Original message------* *From: AE Solar* *Date: Sun, Jun 17, 2018 12:29 PM* *To: RE-wrenches;* *Cc: * *Subject:[RE-wrenches] grounding on metal roofs* *wrenchers,* *what methods are you all using for grounding on metal roofs? thanks* *adam* *Adam KatzmanAutonomous EnergiesPO Box 1245* *Kingston, NY 12402www.autonomousenergies.com <http://www.autonomousenergies.com>(518) 567-1468 <(518)%20567-1468>* *------------------------------* *_______________________________________________List sponsored by Redwood AllianceList Address: RE-wrenches@lists.re-wrenches.org <RE-wrenches@lists.re-wrenches.org>Change listserver email address & settings:http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org <http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org>List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html <http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html>List rules & etiquette:www.re-wrenches.org/etiquette.htm <http://www.re-wrenches.org/etiquette.htm>Check out or update participant bios:www.members.re-wrenches.org <http://www.members.re-wrenches.org>*
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