Thanks Bill, I got it.
From: RE-wrenches [mailto:[email protected]] On Behalf Of [email protected] Sent: Thursday, March 3, 2016 9:07 AM To: 'RE-wrenches' <[email protected]> Subject: Re: [RE-wrenches] NEC 705.12 Point of Connection - 120% rule for center-fed panelboards 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:[email protected]] On Behalf Of Philip Lawes Insoltech Sent: Thursday, March 03, 2016 8:26 AM To: 'RE-wrenches' <[email protected] <mailto:[email protected]> > 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:[email protected]] On Behalf Of [email protected] <mailto:[email protected]> Sent: Wednesday, March 2, 2016 11:24 AM To: 'RE-wrenches' <[email protected] <mailto:[email protected]> > 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:[email protected]] On Behalf Of Glenn Burt Sent: Wednesday, March 02, 2016 10:54 AM To: RE-wrenches <[email protected] <mailto:[email protected]> > 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 <mailto:[email protected]> Sent: 3/2/2016 11:32 To: RE-wrenches <mailto:[email protected]> 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
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