Kirpal, That was always my interpretation as well. So in the case of a 400A service, I can backfeed 400A when utilizing a supply side connection. Others have thoughts on this?
- Mike -- Michael Kelly Project Manager / Project Engineer NABCEP Certified Solar PV Installer ™ SolarFlair Energy, Inc. 11 Mayhew Street Framingham, MA 01702 Direct Mobile: 617-899-9840 Main Phone: 508-293-4293 Main Fax: 508-293-4003 [email protected] On Thu, Mar 4, 2010 at 4:16 PM, Kirpal Khalsa <[email protected]> wrote: > Mike.....i may be wrong....but I think i am right....you are limited by the > wire size feeding the supply and/or the transformer size which supplies the > service.....depending on the physical location of the tap you may be limited > by the enclosure and the enclosure ratings as well > would love to hear any other ideas... > Cheers, > -- > Sunny Regards, > Kirpal Khalsa > > NABCEP Certified Solar PV Installer > Renewable Energy Systems > www.oregonsolarworks.com > 541-218-0201 m > 541-592-3958 o > > > On Thu, Mar 4, 2010 at 12:50 PM, Michael Kelly <[email protected]>wrote: > >> Hi All, >> >> Next to grounding, I find the calculation of the maximum amount of >> backfeed current allowed in a supply side connection to be the most vague >> issue in Article 690. Let's assume we have a 400A, 480/277 service in a >> commercial building, a 400A main service disconnect, and the jurisdiction is >> under NEC 2008. What is the maximum backfeed current allowed in a supply >> side connection? The only place the code points you to is 230.82(6), which >> is no help, or to Article 705, which is no help either. I know that in the >> draft version of NEC 2011, there is an expansion of 705.12(A) which states " >> * *Supply Side. An electric power production source shall be permitted to >> be connected to the supply side of the service disconnecting means as >> permitted in 230.82(6). The sum of the ratings of all overcurrent devices >> connected to power production sources shall not exceed the rating of the >> service." That is a helpful sentence from the Code, but as it is in draft >> form, what do we do under NEC 2008? What have you used as a maximum >> backfeed current for supply side connections? >> >> Thanks, >> Mike >> -- >> Michael Kelly >> Project Manager / Project Engineer >> NABCEP Certified Solar PV Installer ™ >> >> SolarFlair Energy, Inc. >> 11 Mayhew Street >> Framingham, MA 01702 >> Direct Mobile: 617-899-9840 >> Main Phone: 508-293-4293 >> Main Fax: 508-293-4003 >> [email protected] >> >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: [email protected] >> >> Options & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out participant bios: >> www.members.re-wrenches.org >> >> >> > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: [email protected] > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > >
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