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 <mailto: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 <mailto:glenn.b...@glbcc.com> " <glenn.b...@glbcc.com <mailto:glenn.b...@glbcc.com> > Date: Sun, June 17, 2018 6:17 pm To: AE Solar <autonomousenerg...@gmail.com <mailto:autonomousenerg...@gmail.com> > Cc: RE-wrenches <re-wrenches@lists.re-wrenches.org <mailto: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 <mailto: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 Katzman Autonomous Energies PO Box 1245 Kingston, NY 12402 www.autonomousenergies.com <http://www.autonomousenergies.com> (518) 567-1468 <tel:(518)%20567-1468> On Sun, Jun 17, 2018 at 1:46 PM, glenn.b...@glbcc.com <mailto:glenn.b...@glbcc.com> <glenn.b...@glbcc.com <mailto: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 Katzman Autonomous Energies PO Box 1245 Kingston, NY 12402 www.autonomousenergies.com <http://www.autonomousenergies.com> (518) 567-1468 <tel:(518)%20567-1468> _____ _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org <mailto:RE-wrenches@lists.re-wrenches.org> Change listserver email address & settings: 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 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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