Bill, Did I understand your earlier post to infer that there never was an intent to apply the "opposite end of the buss" rule to the 120% backfeed allowance in residential applications? And that you have been working to rewrite a solar backfeed breaker in a residential setting to land anywhere on the buss?
Howie *Howie Michaelson* *NABCEP Certified Solar PV Installer™* Sun Catcher, LLC Renewable Energy Systems Sales and Service VT Solar Electric Incentive Partner 802-272-0004 On Thu, Mar 3, 2016 at 12:07 PM, <billbroo...@sbcglobal.net> wrote: > Phil, > > > > I think you already understand how to apply the “120% rule.” All this is > saying is that the breaker can go at either end of a center-fed panel for > dwellings. Do you understand now? > > > > To summarize—a 200A center-fed panel would allow a 40-amp PV breaker to be > installed at either end to meet the 120% rule. > > > > Bill. > > > > *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On > Behalf Of *Philip Lawes Insoltech > *Sent:* Thursday, March 03, 2016 8:26 AM > *To:* 'RE-wrenches' <re-wrenches@lists.re-wrenches.org> > *Subject:* Re: [RE-wrenches] NEC 705.12 Point of Connection - 120% rule > for center-fed panelboards > > > > Bill, > > Could you please provide an example of this showing calculations? > > Thanks so much, > > Phil > > > > *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org > <re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf Of * > billbroo...@sbcglobal.net > *Sent:* Wednesday, March 2, 2016 11:24 AM > *To:* 'RE-wrenches' <re-wrenches@lists.re-wrenches.org> > *Subject:* Re: [RE-wrenches] NEC 705.12 Point of Connection - 120% rule > for center-fed panelboards > > > > All, > > > > Here is the new language that has been approved for the 2017 NEC (more > authoritative than JW). > > > > 705.12(B)(3)(d) > > > > (d) A connection at either end, but not both ends, of a center-fed > panelboard in dwellings shall be permitted where the sum of 125 percent of > the power source(s) output circuit current and the rating of the > overcurrent device protecting the busbar does not exceed 120 percent of the > current rating of the busbar. > > > > This clarifies that it was never the intent of the NEC to limit the 120% > rule to the opposite end of the busbar for dwellings (it was allowed from > 2005 back to 1987). I was able to convince the panel that centerfed panels > did not need the opposite end stipulation. Several large jurisdictions in > California or considering making an official policy accepting the language > of the 2017 NEC on this item. Please share this with your own jurisdiction. > > > > Bill. > > > > > > *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org > <re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf Of *Glenn Burt > *Sent:* Wednesday, March 02, 2016 10:54 AM > *To:* RE-wrenches <re-wrenches@lists.re-wrenches.org> > *Subject:* Re: [RE-wrenches] NEC 705.12 Point of Connection - 120% rule > for center-fed panelboards > > > > I believe that John Wiles has stated this in a couple of places in print, > therefore you may have a tough time justifying a way around the rule to an > AHJ. > > Supply side connections are very popular in this situation. > ------------------------------ > > *From: *August Goers <aug...@luminalt.com> > *Sent: *3/2/2016 11:32 > *To: *RE-wrenches <re-wrenches@lists.re-wrenches.org> > *Subject: *[RE-wrenches] NEC 705.12 Point of Connection - 120% rule for > center-fed panelboards > > All – > > > > We are seeing more AHJs not allowing us to use the NEC 7015.12(D)(2)(3)(b) > 120% rule on center-fed panelboards. For example, if we have a 100 A > meter/main combo with a center fed 100 A breaker we cannot apply the 120% > rule at all and need to do a panel swap. What are other wrenches doing in > this case? > > > > Best, > > > > August > > Luminalt > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: 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 > > Check out or update participant bios: > www.members.re-wrenches.org > > >
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