Re: [RE-wrenches] calculating DC voltage drop

[Allan Sindelar]

Mike, I would respectfully challenge both reasons ;^)} . The responses already posted today cover them: you don't need to compensate for intermittent high-insolation conditions when sizing for voltage loss, as this is not a Code issue; Code addresses ampacity and OCP issues. And being conservative means you add unnecessarily to wire cost (sometimes substantially at 25% greater current) when that money could be better spent on more PV, with an ultimately greater annualized return of total energy per $$ spent. Ray Walters' recent posts cover this well. Allan Sindelar Allan@positiveenergysolar.com NABCEP Certified Photovoltaic Installer EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com On 7/22/2010 3:53 PM, Michael Kelly wrote: Allan,   I use Imp*1.25 because NEC calls out a 125% adder for unexpected high-insolation conditions (snowscapes, cloud effect, yellow houses next door, etc).  And because I am an engineer and like to be conservative :).   -Mike --- Michael Kelly Applications Engineer NABCEP Certified Solar PV Installer ™ Solectria Renewables, LLC 360 Merrimack St. Building 9, Floor 2 Lawrence, MA 01843 Phone: 978-683-9700 ext. 167 Fax: 978-683-9702 m...@solren.com www.solren.com   From: Allan Sindelar [mailto:al...@positiveenergysolar.com] Sent: Thursday, July 22, 2010 5:26 PM To: m...@solren.com; RE-wrenches Subject: Re: [RE-wrenches] calculating DC voltage drop   Mike, Why do you make this exception, please? Allan Sindelar Allan@positiveenergysolar.com NABCEP Certified Photovoltaic Installer EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com   _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org 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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