<div dir="ltr"><div dir="ltr"><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">We do high-leg Delta commercial jobs occasionally, although I have never done a battery backup, but it should not matter if they are only using the two 120V legs to supply 120/240V split-phase service. The A and C legs of 120V to neutral should be 180 degrees out of phase with each other and work fine with any split-phase inverter. Just make sure you are not using the wild leg that is 208V to neutral, if that is even delivered to the customer from the utility.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Most of the time, what we see is a 4-wire delivery to the customer with a 3-phase panelboard, and every third breaker space is empty. They are only using 120V and 240V circuits. We find this in light commercial settings in older industrial parks.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">The other thing to consider is whether the utility will have an issue with an unbalanced backfeed. FPL does not care around here as long as it's under 50kWac. They allow netmetering on two legs of a 240V delta high-leg service.</div></div><div><div dir="ltr" class="gmail_signature"><div dir="ltr"><br>Jason Szumlanski<div><span style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px">Principal Solar Designer | Florida Solar Design Group</span><br style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px"><span style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px">NABCEP Certified Solar Professional (PVIP)</span><br style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px"><span style="color:rgb(51,51,51);font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:13px">Florida State Certified Solar Contractor CVC56956</span></div><div><font color="#333333" face="Roboto, RobotoDraft, Helvetica, Arial, sans-serif">Florida Certified Electrical Contractor EC13013208</font></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Mar 25, 2026 at 11:54\u202fAM Michael Morningstar via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Wrenches,</div><div>I have a customer that has asked me to provide their restaurant with PV and battery back up. Easy-peasy or so I thought. It turns out that the service that supplies the restaurant is being fed by two phases from a 120/240V transformer. The service entrance conductors are direct burial and run under a large paved parking lot, so there's no changing that arrangement. I'm at a loss as what I can do here. I don't believe that something like a Sol-Ark 18k is going to play nice with two legs 120 degrees out of phase? The 30K definitely needs all three phases so a 240 Delta/208 WYE isn't going to help? I don't even think there are micro-inverters or string inverters available to give them just straight grid-tied and no BB. Are there any solutions that I'm unaware of?</div><div>Michael</div><div>?</div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr">
<p style="margin:0px;font:18px Helvetica;min-height:22px"><span></span></p>
<p style="margin:0px;font:18px Helvetica">Michael Morningstar </p><p style="margin:0px;font:18px Helvetica"><br></p><p style="margin:0px;font:18px Helvetica">Morningstar Electric Inc</p><p style="margin:0px;font:18px Helvetica">PO Box 1494</p><p style="margin:0px;font:18px Helvetica">Mount Shasta, CA 96067</p><p style="margin:0px;font:18px Helvetica">530-921-0560</p><p style="margin:0px;font:18px Helvetica">CSLB 1116835</p><p style="margin:0px;font:18px Helvetica"><a href="mailto:mjmorningstar@gmail.com" target="_blank">mjmorningstar@gmail.com</a></p><p style="margin:0px;font:18px Helvetica"><br></p></div></div></div>
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