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). It may contain confidential or privileged information that may be exempt from disclosure under applicable law. If you are not the intended recipient(s), you are notified that the disclosure, dissemination, distribution, copying, storing, or other use of the contents of this message or its attachments is strictly prohibited. If you receive this message in error, or are not the named recipient(s), please notify the sender at either the email address or telephone number above and delete this email from your computer. Thank you. _______________________________________________ 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
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