Kent, Situations vary but this one line helps a lot, thanks.
So, "To PV System" would go to the output of a grid tie inverter and "To Backed Up Loads" would go to the AC IN (transfer switch) of a battery inverter. I have been going to homes with existing 100A gen/utility ATS and wondering if I could keep it as is and be able to add a grid tie battery backup to it (using same backup loads). This schematic would work in that situation as well but wouldn't have the "To Non-Backed UP Loads" tap. Larry Liesner Wirewiz Westport, CT Phone: 203-644-2404 Fax: 203-557-0556 wire...@gmail.com www.wire-wiz.com On Mar 27, 2011, at 2:36 PM, Kent Osterberg wrote: > Larry, > > Situations vary so much that this might not be very useful. But here you go. > The attached sketch shows how we recently connected a customer that had a > backup generator and transfer switch that wasn't service rated. There were > nice gutters existing from the original install so accessing points to tap > conductors wasn't difficult. We could have connected the inverters to the > non-backed upped loads panel instead, but the utility requires an accessible > disconnect by the meter so it was more convenient to just get into the gutter. > > Kent Osterberg > Blue Mountain Solar > > > > wire...@gmail.com wrote: >> >> Kent, Jason, or anyone else >> >> Would you a have a simple one-line you could share for wiring the inverter >> on the utility side of the transfer switch? >> >> Thank you. >> >> Larry Liesner >> Wirewiz >> Westport, CT >> Phone: 203-644-2404 >> Fax: 203-557-0556 >> wire...@gmail.com >> www.wire-wiz.com >> >> >> >> On Mar 26, 2011, at 6:04 PM, Jason Szumlanski wrote: >> >>> We’ve explored this strategy many times due to all of the whole house and >>> critical load generators in Florida. We’ve stayed away from the contactor >>> solution because of the potential for the NC contactor failing to open, >>> keeping the inverters “online” when transferred to generator power. While >>> unlikely, this is a possibility that must be considered. >>> >>> The other issue presented here is that the inverters will shut down every >>> time the generator exercises. >>> >>> The only sure-fire way seems to be wiring the inverter on the utility side >>> of the transfer switch, as Kent said. >>> >>> Jason Szumlanski >>> Fafco Solar >>> >>> >>> From: re-wrenches-boun...@lists.re-wrenches.org >>> [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kent >>> Osterberg >>> Sent: Saturday, March 26, 2011 5:56 PM >>> To: RE-wrenches >>> Subject: Re: [RE-wrenches] Generator and Enphase >>> >>> Mark, >>> >>> I agree it is best to wire the inverters on the utility side of the >>> transfer switch. When that isn't easy, a normally closed contactor that is >>> opened by generator voltage, will isolate the inverters from the generator >>> and allow automatic return to utility operation when the generator is off. >>> >>> Kent Osterberg >>> Blue Mountain Solar >>> >>> >>> >>> Mark Frye wrote: >>> Eric, >>> >>> I do not have direct experience with this but have been exploring the issue >>> for a project I am currently doing. >>> >>> My response will be to take the trouble to interconnect the Enphase >>> inverters on the line side of the tranfer switch so that the inverters can >>> never be connected to the generator. >>> >>> Here are the reasons why: >>> >>> 1 - Enphase states that any such application is considered an "off-grid" >>> application which voids their warrenty. As I am installing under the >>> California CSI program, I am required to provide a 10 year manufacture >>> equipment warranty so I cannot afford to install the inverters in a >>> dis-allowed manner. >>> >>> 2 - Enphase states that the waveform of the generator may be "clean" enough >>> such that the inverter may attempt to syncornize and connect to it as if it >>> were the utility. If this were to happen Enphase believes the inverters >>> will ruin the generator regulator before the generator ruin the inverter. I >>> don't want to be the one to run the experiment to find out which would be >>> which. >>> >>> 3 - I considered a contactor on the output of the inverters, such that the >>> inverters would isolated by a loss of line voltage, requiring some form of >>> reset. Ulitmately my customer agreed with me that this was an undesirable >>> constraint on the operation of an otherwise reliable grid-tied system and >>> it was not clear that this would satify the warranty issue. >>> >>> Mark Frye >>> Berkeley Solar Electric Systems >>> 303 Redbud Way >>> Nevada City, CA 95959 >>> (530) 401-8024 >>> www.berkeleysolar.com >>> >>> >>> From: re-wrenches-boun...@lists.re-wrenches.org >>> [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Eric Thomas >>> Sent: Saturday, March 26, 2011 2:09 PM >>> To: re-wrenches@lists.re-wrenches.org >>> Subject: [RE-wrenches] Generator and Enphase >>> >>> I have a customer with a "30A Mechanically Interlocked Breaker" for their >>> generator feed at the main panel. My question is: If the home power is >>> transferred from utility to generator power, will the backfed PV see the >>> generator as grid power and sync up and produce? This is a nice Honda >>> Generator so the power should be fairly clean. Any experiences are >>> appreciated. >>> >>> Take Care, >>> >>> >>> Eric Thomas >>> Solar Epiphany LLC >>> (206) 919-3014 >>> www.solarepiphany.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 >>> >> >> >> _______________________________________________ >> 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 >> >> > <OneLine.JPG>_______________________________________________ > 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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