We've just started having problems with PG&E and NEM applications for somewhat larger residential systems (12 kW). The NEM process is bass-ackwards in that you install and pay for the system, THEN apply for the interconnection. Never been a problem before, but with a recent 12 KW application, PG&E said the transformer was too small. We had to get the customer to sign a letter that he would only operate 41 of the 44 modules installed (not that we can disconnect 3 modules in a string system). That would allow the interconnection to go forward until the utility could upgrade the transformer at their expense, in a "few months", and only because it was shared with another customer's service. If it had been a dedicated transformer to the customer, he would have been responsible for the cost of an upgrade. (Eventually the utility said "never mind, operate the whole system".)
We had another 12 kW system coming up, and to be sure we didn't get into a deal-killing problem, I tried to find out in advance if the transformer was adequate. We did step one of the application (the "Agreement and Customer Authorization" form, which specifies CEC-AC rating and annual usage, but not specific equipment). Waited several weeks with no word, then with the job schedule approaching, tried several times to speak to someone. Finally got someone who said " it will probably work, but it needs to be reviewed by engineering", so we need to submit step 2 of the forms, which normally they won't accept unless it's accompanied by the finalled building permit. Catch 22. He said they would "try to work around that". I also asked how a transformer supplying a 200 amp service could not accept 49 amps maximum backfeed, and was told "just because it's feeding a 200 amp panel doesn't mean it's rated for 200 amps. The transformer is only sized to the projected load which could be smaller." I asked how backfeeding is considered load, and was told about possible problems with "flicker factor." So, still waiting to see if I have to give my customer the choice of paying for a $10,000 plus transformer upgrade or downsizing the system. Downsizing to what size? Seems like we would still need guidance on the transformer capacity. This has NEVER been an issue before. Bruce Erickson Mendocino Solar Service PO Box 1252 Mendocino, CA 95460 707-937-1701 707-937-1741 fax [email protected] Celebrating 20 Years in Solar! 1994-2014 On Jan 16, 2015, at 9:38 PM, jay peltz wrote: > I am just asking about any advice for the paperwork process above 30kW with > pg&e as I've never done one this large for a residence. > > Customer has a standard 400 amp 240v single phase connection. > > Thanks > > Jay > > Peltz power > > > > On Jan 16, 2015, at 5:25 PM, Jerry Shafer <[email protected]> wrote: > >> Well when you get that large the 3 phase makes a difference >> >> On Jan 16, 2015 5:23 PM, "William Miller" <[email protected]> wrote: >> Friends: >> >> >> >> I would hesitate before offering three phase to a residential installation. >> Well pumps, booster bumps and other appliance, if configured for 230 volts >> do not operate well with 208 volts. They may work but you reduce your >> margin for voltage drop. >> >> >> >> William >> >> >> >> >> >> <image003.jpg> >> Lic 773985 >> millersolar.com >> 805-438-5600 >> >> >> >> >> > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/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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