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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Yes, each situation is different. Very rarely do we find ourselves saying, “hey, this is just like the Jones/Smith job.”<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The only thing I would comment on is that in the case of a whole house generator, there would not be a “non-backed up loads” line on the drawing. All loads would be on the transfer switch and there is no choice but to do a service side connection.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Jason Szumlanski<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Fafco Solar</span><span style='font-size:4.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Kent Osterberg<br><b>Sent:</b> Sunday, March 27, 2011 2:37 PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Generator and Enphase<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Larry,<br><br>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.<br><br>Kent Osterberg<br>Blue Mountain Solar<br><br><br><br><a href="mailto:wirewiz@gmail.com">wirewiz@gmail.com</a> wrote: <o:p></o:p></p><p class=MsoNormal>Kent, Jason, or anyone else <o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Would you a have a simple one-line you could share for wiring the inverter on the utility side of the transfer switch? <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Thank you.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><div><div><div><div><div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Larry Liesner<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Wirewiz<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Westport, CT<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Phone: 203-644-2404<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Fax: 203-557-0556<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'><a href="mailto:wirewiz@gmail.com">wirewiz@gmail.com</a><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'><a href="http://www.wire-wiz.com">www.wire-wiz.com</a><o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'><o:p> </o:p></span></p></div></div></div></div></div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Mar 26, 2011, at 6:04 PM, Jason Szumlanski wrote:<o:p></o:p></p></div><p class=MsoNormal><br><br><o:p></o:p></p><div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>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.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The other issue presented here is that the inverters will shut down every time the generator exercises.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The only sure-fire way seems to be wiring the inverter on the utility side of the transfer switch, as Kent said.</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><div><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Jason Szumlanski</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Fafco Solar</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p></div><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><div><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span class=apple-converted-space><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> </span></span><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'><a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a><span class=apple-converted-space> </span>[<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>]<span class=apple-converted-space> </span><b>On Behalf Of<span class=apple-converted-space> </span></b>Kent Osterberg<br><b>Sent:</b><span class=apple-converted-space> </span>Saturday, March 26, 2011 5:56 PM<br><b>To:</b><span class=apple-converted-space> </span>RE-wrenches<br><b>Subject:</b><span class=apple-converted-space> </span>Re: [RE-wrenches] Generator and Enphase</span><o:p></o:p></p></div></div></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>Mark,<br><br>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.<br><br>Kent Osterberg<br>Blue Mountain Solar<br><br><br><br>Mark Frye wrote:<o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:blue'>Eric,</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:blue'>I do not have direct experience with this but have been exploring the issue for a project I am currently doing.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:blue'>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.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:blue'>Here are the reasons why:</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:blue'>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.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:blue'>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.</span><o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:blue'>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.</span><o:p></o:p></p></div><div><p class=MsoNormal> <br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Mark Frye</span><span class=apple-converted-space> </span><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Berkeley Solar Electric Systems</span><span class=apple-converted-space> </span><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>303 Redbud Way</span><span class=apple-converted-space> </span><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Nevada City, CA 95959</span><span class=apple-converted-space> </span><br><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>(530) 401-8024</span><span class=apple-converted-space> </span><br><a href="http://www.berkeleysolar.com/"><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>www.berkeleysolar.com</span></a><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> </span><o:p></o:p></p></div><div><div><p class=MsoNormal> <o:p></o:p></p></div></div><div><p class=MsoNormal> <o:p></o:p></p></div></div></div></div><pre> <o:p></o:p></pre></div></body></html>