Hi Bruce, I have had the exact same issue on one site. Sunpower branded SMA -22 inverter (7kw or 7.7 kw, I don't remember off the top of my head) and an SMA RSB. This was a DPW TPM a couple hundred feet from the basement. The inspector made us retrofit a RSB on the side of the house, since the conductors were on the house for barely more than 10' before the inverter. We were getting a self-test fail many nights, but then generally in the morning it would pass. Occasionally it would not pass in the morning, and then the inverter would not produce power until someone power cycled the inverter.
When I inspected this one I found moisture in the RSB due to condensation and poor job sealing the conduit coming from the house. I assumed that the RSB was bad. We removed the RSB from that site and the issue has not come back. Out of curiosity, I then installed the same RSB on our warehouse (has a 5kw -22 inverter) and there have been no issues there. We have not yet installed a new RSB at the site with the original issue. We have installed about 10-15 of the boxes, and only one other one has had an issue. Not my favorite piece of equipment. I am curious to hear if you get the source of this figured out. I had talked to both Sunpower and SMA at the time of this issue, and neither was able to give much help. Cheers, Dave *--* *Dave Tedeyan* *Project Engineer* *Taitem Engineering, PC* 10 Verizon Lane, Lansing, NY 14882 Voice: (607) 930-3481 x6 www.taitem.com On Sat, Sep 30, 2017 at 11:57 AM, Drake < drake.chamber...@redwoodalliance.org> wrote: > The TL-22s are notorious for nuisance arc fault tripping. Is your array on > a metal roof? Large metal roofs can amplify RF signals and cause tripping. > > At 05:32 PM 9/29/2017, you wrote: > > Hi All, I’m wondering if anyone else is having trouble with the SMA >> Rapid Shutdown Box. We have an installation where an SMA 7700TL-US-22 >> (rebranded as SunPower) is fed by an array with a Rapid Shutdown Box. Many, >> but not all, mornings, the inverter would fail the AFCI self-test on >> wakeup. When reset, it would operate fine all day. There was never an >> actual indication of an arc fault, just the self-test failure. SunPower, in >> consultation with SMA, decided to replace the inverter. Everything worked >> normally for a couple of weeks, then the problem resumed. Again, no >> arc-fault indication, just the self-test failure and then full operation >> the rest of the day after resetting. We began to suspect the Rapid Shutdown >> Box, so we bypassed it completely, and there were absolutely no problems >> for several weeks. SMA was then willing to replace the RSB, after which >> everything worked fine for about a week, then this morning the same issue. >> Again, self-test failure, then when reset, it has to go through another >> self-test, which it always passes and then runs all day. Has anyone had >> problems with the RSB, or, with AFCI in general? Based on this experience, >> this is the second and last RSB we’ve used, and have somewhat reluctantly >> gone to all micro inverters to meet rapid shutdown. Bruce Erickson >> Mendocino Solar Service PO Box 1252 Mendocino, CA 95460 707-937-1701 >> 707-937-1741 fax br...@mendocinosolar.com Connecting Mendocino County to >> Solar Since 1994 _______________________________________________ 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-wren >> ches.org List-Archive: http://www.mail-archive.com/re >> -wrenc...@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 >> > > _______________________________________________ > 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.or > g/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > _______________________________________________ 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
