Thanks for the reply and article, August. John Wiles's article makes a clear statement that the GEC is not required for TL inverters. I wish the code would say it that clearly! I think I'm going to have a tough time convincing inspectors the GEC isn't required with such unclear language in the code. We'll see....
Thanks again! Dana Dana Brandt Ecotech Energy Systems, LLC www.ecotechenergy.com [email protected] 360.318.7646 On Mon, Nov 3, 2014 at 12:45 PM, August Goers <[email protected]> wrote: > Hi Dana, > > > > This is still a confusing issue, I agree. This article helps a bit: > > > > http://www.nmsu.edu/~tdi/pdf-resources/IAEI%20Mar_Apr%202012.pdf > > > > If you look in a SMA TL inverter installation manual, for example, they > only mention equipment grounds – there is no reference to a GEC that I can > find. The 2014 code doesn’t seem to have clear wording on not requiring a > GEC to me but Rebekah’s recap below is spot on. Luckily it is widely > accepted in our neck of the woods that TL inverters don’t need GECs. > > > > I’m not familiar with the Solectria TL product. It sounds like it will be > best to call them if you need to install one of their inverters. > > > > Best, > > > > August > > > > *From:* RE-wrenches [mailto:[email protected]] *On > Behalf Of *Dana Brandt > *Sent:* Monday, November 03, 2014 12:06 PM > *To:* RE-wrenches > *Subject:* Re: [RE-wrenches] Code reference request > > > > I think I'm a bit confused on this point. I can't seem to find the code > that specifically exempts the GEC requirement for inverters of ungrounded > PV systems. The only exception I can find is only for AC PV modules (2014 > NEC 690.47 (C) ). > > I just looked in the installation manual for Solectria's new TL inverters > and found this: > "Per NEC 690.47, a GEC must be installed, and the Grounding Electrode > Terminal (GET) conductor must be sized in accordance with NEC article > 250.166." > > What am I missing? > > Thanks, > > > Dana > > Dana Brandt > Ecotech Energy Systems, LLC > www.ecotechenergy.com > [email protected] > 360.318.7646 > > > > On Tue, Oct 28, 2014 at 11:30 AM, Rebekah Hren < > [email protected]> wrote: > > If you are on 2014: > > 690.47(B) > > An ac equipment grounding system shall be permitted > > to be used for equipment grounding of inverters and other > > equipment *and for the ground-fault detection reference for * > > *ungrounded PV systems.* > > > > and 690.47(C)(3) > > *For ungrounded systems, this conductor shall be sized in accordance with > 250.122 *and shall > > not be required to be larger than the largest ungrounded > > phase conductor. > > > > On Tue, Oct 28, 2014 at 2:22 PM, Gary Willett < > [email protected]> wrote: > > Kirk: > > A DC grounding electrode conductor (GEC) is not required for inverters > that do NOT have a ground reference for the PV+ and PV- conductor(s) from > the PV array. > > A GEC is not required if the string inverter is one of the new TL > (transformerless) types. Also, this applies to micro-inverters such as the > new Enphase M250 and later versions of the M215. > > Where this applies, only a properly sized equipment grounding conductor > (EGC) is required. > > The EGC is sized according to [NEC 690.45] and can be a minimum of #14AWG > when not exposed to damage, or #6AWG when exposed to potential damage. > > Regards, > > Gary Willett PE > Icarus Engineering LLC > > > > On 10/28/14, 12:53 PM, Kirk wrote: > > Hi, > I'm on a jobsite without my code book. Could someone tell me where in the > code ungrounded systems do not require the inverter GEC? Basically my > onsite electrician doesn't believe me. Thanks. > > Kirk Herander > VSE > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > > > > -- > > Tel: 336.266.8800 > http://o2energies.com/ > Project Engineer > NABCEP Certified PV Installation Professional™ 091209-85 > NC Licensed Electrical Contractor > > This message, together with any attachments, is intended only for the > named recipient(s). 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