[RE-wrenches] 120/240 Delta

[pieter offgridenterprises.org]

I would suggest that you confirm the service configuration first. You could have an open Delta, or less likely a high leg delta. Typically  ahigh leg Delta will have four current carrying conductors supplying the MDP.
[The Wild Leg]
 An open Delta also has a 180 degree relation ship, but is less efficient and you have to be cognizant about creating voltage imbalances.
[https://i.sstatic.net/x5RgQ.jpg]
In either case you have multiple options, but I recommend engaging a PE to help you do it correctly. There is more involved than simply getting the voltages correct.
Pieter Huebner
Project Manager
Off Grid Enterprises

________________________________
From: RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org> on behalf of Sue Stankevitz via RE-wrenches <re-wrenches at lists.re-wrenches.org>
Sent: Wednesday, March 25, 2026 1:14 PM
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Cc: Sue Stankevitz <Sue at midnitesolar.com>
Subject: Re: [RE-wrenches] 120/240 Delta


The Rosie7048RE will do 120/208 with just a setting adjustment.



Sue Stankevitz
MidNite Solar, Inc.<https://www.midnitesolar.com/index.php>
(360) 403-7207 (XT122)

[cid:image001.gif at 01DCBC61.B1521B30]



From: RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org> On Behalf Of Michael Morningstar via RE-wrenches
Sent: Wednesday, March 25, 2026 11:54 AM
To: RE-wrenches <re-wrenches at lists.re-wrenches.org>
Cc: Michael Morningstar <mjmorningstar at gmail.com>
Subject: [RE-wrenches] 120/240 Delta



Wrenches,

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?

Michael

?

--

Michael Morningstar



Morningstar Electric Inc

PO Box 1494

Mount Shasta, CA 96067

530-921-0560

CSLB 1116835

mjmorningstar at gmail.com<mailto:mjmorningstar at gmail.com>


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