Jeff, My memory also recalls something about a 6kW value.
I've talked to one of our local utilities about this as well and they base the accepted imbalance by the size of the transformer serving the building. I have never read their white paper on the subject though. When I described a similar situation for an install we were working on, the engineer acknowledged that he would not have any concern with such an arrangement. You may approach your utility and see if they have a standard protocol you could follow for your system. Ryan -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jeff Clearwater, Village Power Design Sent: Thursday, August 07, 2008 10:14 AM To: RE-wrenches Subject: [RE-wrenches] Imbalanced Legs in 3-Phase systems Hi Wrenches, How does one determine how much imbalance can be tolerated on a 3 phase system? I'd like to feed 2 SMA SB5000s at 277 VAC into a 480 VAC panel instead of 1 13 KW Solectria at 480VAC as the PV system is only 9500 Watts STC. The main on the backfed service panel is 600 A. But I'm not that sure of the loads as it's new construction and hasn't been characterized. What are the appropriate calcs to do here? Thanks! Jeff C. -- ~~~~~~~~~~~~~ Jeff Clearwater Village Power Design Sustainable Energy & Water Solutions for Home & Village http://www.villagepower.com [EMAIL PROTECTED] NABCEP (tm) Certified Solar PV Installer Voice: 413-259-3776 Fax: 413-825-0703 65 Schoolhouse Rd Amherst, MA 01002 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`~ _______________________________________________ List sponsored by Home Power magazine RE-wrenches@lists.re-wrenches.org http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database: 270.5.12/1597 - Release Date: 8/7/2008 5:54 AM _______________________________________________ List sponsored by Home Power magazine RE-wrenches@lists.re-wrenches.org http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
