Hi Ray and Dan and Chris, etc, I agree with a lot of what you are saying, don't get me wrong...I have an off-grid house too and I've been worrying about how module level shutdown will be implemented and what it means for reliability and cost, especially dc-coupled battery-based systems that really don't have or need MLPE.
I'm working on article for the Sept/Oct Homepower about rapid shutdown and one the things I've been excited to learn about is the new Sunspec alliance power line communication protocol <https://www.solarpowerworldonline.com/2017/10/communicating-get-job-done-inverters-sunspecs-rapid-shutdown-standard/> for receivers and transmitters for RS. As Ray mentioned Midnite is already selling their SOB <http://www.midnitesolar.com/productPhoto.php?product_ID=671&productCatName=Software&productCat_ID=44&sortOrder=1&act=p> (er, haha). And Tigo just got their cheapest RS MLPE option the TSF-F UL <https://www.tigoenergy.com/library/view/TS4-F+-+Fire+Safety.pdf/> listed. What's cool is the devices are inverter-agnostic, and don't need another conductor for data or power running to them. But as Ray also said, they aren't working with charge controllers, yet. So I do think there is some good news on the horizon! From the way the 2020 NEC first draft is written, I don't perceive any chance of the 690.12 rules really changing drastically. But something else that may change the products we can use to meet the requirements is a new UL standard that is being worked on- UL 3741 PV Hazard control. I don't know much about it, but here is a list of the people <https://csds.ul.com/Include/ViewRoster.aspx?GroupID=1782&stpNumber=3741> who are on the Standards Technical Panel. I think a few of them are on this listserv so maybe one of them will give us an update! Best, Rebekah On Fri, Jul 6, 2018 at 4:39 PM Ray <r...@solarray.com> wrote: > > > > -------- Forwarded Message -------- > Subject: Re: [RE-wrenches] Rapid Shutdown and January 1 2019 option? > Date: Fri, 6 Jul 2018 16:37:47 -0600 > From: Ray <r...@solarray.com> <r...@solarray.com> > To: Rebekah Hren <rebekah.h...@gmail.com> <rebekah.h...@gmail.com> > > Hi Rebekah; > > I very much appreciated your previous posts on this. Yes, we do not need > to disconnect the inverter and battery per previous interpretations. > However, the RS system can and will trip for a variety of reasons, which > disconnects the charging system. It might take a couple of days to > discharge the batteries, but the results are the same: rotten meat in the > fridge and a dead battery. If no one is home, thousands of dollars of > battery could be ruined in a matter of weeks, if its Gel or AGM. > > If we get to a point where all the modules have shut down built in, and > the Controllers also have built in disconnect so their capacitors don't > back feed, then it won't be so hard to comply with 690.12. In the mean > time though, off grid should be given a clear exemption based on array size > and Voc of the array. We are often only wiring 2 modules in series, so we > are already well below 100 v. Rules designed for 600 v arrays should not > unilaterally apply to everyone, just as 600 VAC rules don't all apply to > 120 vac residential. There are numerous exemptions for lower voltage AC > situations, we are just asking that the same thinking be applied to PV. > > Ray Walters > Remote Solar > 303 505-8760 > > On 7/6/18 2:57 PM, Rebekah Hren wrote: > > I believe there was a big improvement for off-grid systems as relates to > RS in the 2017 NEC - the diagrams in 690.1(b) all show the PV system > disconnect clearly now. If you check out the diagrams you can see that > energy storage/battery circuits, including the battery-based inverter > whether AC or DC coupled, are outside the PV system boundary, thus not PV > system circuits, thus not subject to RS. > > Also, the NEC 2020 1st draft report has been published > <https://downloads.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=70&tab=nextedition>, > so get your comments submitted! > > Rebekah Hren > Member, NEC CMP-4 > > On Fri, Jul 6, 2018 at 2:22 PM Dan Fink <danbo...@gmail.com> wrote: > >> I agree with you, Ray, as a purely off-grid solar installer and >> troubleshooter. I think all that was accomplished in NEC 2017 on this issue >> is that non-habitable structures, like the common off-grid 'power shed' >> don't need 690.12 RS anymore. >> >> Dan Fink >> Professor of Solar Energy Technology, Ecotech Institute >> IREC Certified Instructor™ for: >> ~ PV Installation Professional >> ~ Small Wind Installer >> Executive Director, Buckville Energy >> NABCEP Registered Continuing Education Providers™ >> NABCEP Associate >> >> 970.672.4342 >> >> >> >> On Fri, Jul 6, 2018 at 11:32 AM, Ray <r...@solarray.com> wrote: >> >>> Midnite has some string level and module level 690.12 disconnects that >>> wire in like an optimizer or micro inverter, so those should be able to >>> meet the 2019 requirements. However beware: they as of yet still don't >>> have a reasonable disconnect system to disconnect the charge controller >>> which has capacitors that back feed the PV line for up to 90 seconds. They >>> have a DC GFI breaker with remote trip capability but it takes 4 spaces, so >>> with multiple charge controllers it turns into a wiring mess really fast. >>> >>> I actually wired in some 60 amp rated diodes on one system to get it to >>> pass inspection; what a joke, going back to 1980s equipment to pass 2017 >>> code. 690.12 is an absolute nightmare for small off grid. There really >>> should be some exemptions for small arrays (under 3 kW) and under 100 vdc. >>> Fire fighters are not going to get there till the structure is down >>> anyway, Response times are up to an hour for remote locations with >>> volunteer fire departments. Its not like in town at all; no one is going >>> to go on the roof on an off grid fire. >>> >>> On the flip side, there are real dangers created by nuisance tripping of >>> 690.12 equipment. Again, on grid it's a mere inconvenience, but off grid >>> it could mean spoiled food, frozen water lines, shut down heating systems >>> in subzero temperatures, and for the elderly: loss of their breathing >>> machines. I've already had a 74 year old customer climbing on their roof >>> multiple times to reset the Rapid shutdown equipment after nuisance trips. >>> Are we going to wait until we get someone killed in the name of "Safety" >>> before we fix this? >>> >>> Ray Walters >>> Remote Solar >>> 303 505-8760 >>> >>> On 7/6/18 9:55 AM, cwarfel wrote: >>> >>> I am wondering about the experience installers have with a DC coupled >>> multimode system design that will comply after January 1 with what I >>> feel is the biggest mistake/poorly guided part of NEC 2017 690, and that >>> is 690.12. We are installing two Outback systems with the remote c >>> ontrolled combiner and even that won't comply after January 1 unless we >>> parallel >>> more subarrays (There's safety for you, lower voltage-higher amperage!). >>> Thanks for any insight. >>> >>> Chris >>> >>> >>> >>> >>> -- >>> >>> Christopher Warfel, PE >>> ENTECH Engineering, Inc. >>> PO Box 871, Block Island, RI 02807 >>> (401)466-8978 >>> >>> [image: EEI logo] <http://entech-engineering.com> >>> >>> >>> _______________________________________________ >>> 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 >>> >>> >>> >>> _______________________________________________ >>> 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 >>> >>> >>> >> _______________________________________________ >> 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 >> >> > > -- > Tel: 336.266.8800 > NABCEP Certified Solar PV Installation Professional™ 091209-85 > NC Licensed Electrical Contractor > > > _______________________________________________ > 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 > > > _______________________________________________ > 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 > > -- Tel: 336.266.8800 NABCEP Certified Solar PV Installation Professional™ 091209-85 NC Licensed Electrical Contractor
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