Jerry:
Thanks for the reply. If we go three phase I believe we get to pick our voltage. I understand the options are 120/208, 120/240 (open delta) or 277/480. 277/480 won’t work for us because of existing equipment operating at 240 VAC. We have very few 120 loads so a stinger won’t hurt my feelings—I would pick the 120/240. I can do an AB/AC/BC installation with many residential inverters, but at the less than 10K this become problematic: We actually need to split the 10K system size into a 4K and a 6K to offset annual kWh on two meters. By the time you divide these smaller systems into 3 inverters, you don’t have enough panels to meet the MPPT lower threshold. This is where Enphase actually makes some sense. Furthermore, too many string inverters makes the job expensive. It looks like there are real three phase inverter options and I will keep looking. I won’t touch a Fronius. The new equipment may be improved, but I am still burnt by a 500% failure rate of IG inverters and some serious character assassination by Fronius management in dealing with clients. I misquoted the $20K cost to upgrade. This number came from an earlier hypothetical scenario. I need to get real numbers for this project to perform an accurate budget analysis. Thanks for the great input, both online and offline. I feel like we are family. While the complexities of these projects can be a headache, they make the job interesting. William *From:* Jerry Shafer [mailto:jerrysgarag...@gmail.com] *Sent:* Wednesday, January 16, 2019 1:12 PM *To:* William Miller; RE-wrenches *Subject:* Re: [RE-wrenches] Cost of service upgrade vs Solar credits William, Wrenches, can we assume the utility voltage is 120/208 of so Fronius has some inverters that do that, if it is 277/480 then SMA can do that but neither of them are less then 10k, Enphase does not have a 3 leg inverter just 1/2,2/3/,3/1 leg balance but you can do that with most any single phase inverter. We have had several customers that got hit with Xformer upgrade charges at time of PTO which is a real problem. I agree that is you go solar that the bill would be close to zero now that would trigger the 20 k bill to your customer, better off paying it now and getting FTC while you can. Jerry On Wed, Jan 16, 2019 at 12:30 PM William Miller <will...@millersolar.com> wrote: Friends: I am engaged in a rather complicated decision process regarding an AG customer in PG&E territory. The customer spends a lot of money pumping water and wishes to offset that cost with installation of a grid-tied system. His two services are decrepit and have to be upgraded. There was some question if he will be required to upgrade from single phase to three phase given the size of his motor loads. We received a waiver to allow us to continue with single phase although I am not sure that is the right decision. We were also informed that the $20,000 cost to upgrade the single phase feeder to allow bigger services would be waived because of the potential revenue PG&E would earn over time. There is a review three years out and if the revenue meets projections based on existing loads, the construction credit would remain. If, however, after three years revenue decreased, the credit would be rescinded, requiring the customer to fork over the 20 grand. I was told that if we install solar and zero out the annual bill, that reduction in billing would trigger the rescinding of the credit. I want to check that the utility is interpreting this correctly. Do any of you esteemed wrenches have any experience in this area? Another question: If we go three phase and I wish to use inverters with two hot leads, I know they will work on three phase, but the back-feed will be imbalanced. I know we are allowed some amount of imbalance, but I am not sure how much. Anyone know this answer? I am searching for true three phase inverters in the less than 10kW range. This would require a connection to all three phases. I believe Enphase can do this. Are there any other units you know of? Thanks, William _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
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