If it is a TL, there is a combiner input, and yes, you can use no fuses for two strings.
On Mon, Oct 6, 2014 at 6:27 PM, William Miller <[email protected]> wrote: > Mike: > > > > If I have just two strings of Solarworld SW275 modules per inverter, can I > use one input to the built-in combiner to feed in a combined string? My > calculations indicate that I might be able to feed the two strings into one > 25 amp KLKD fuse. The Isc is 8.94. times 1.25 = 11.715. Times 2 = 22.35. > > > > The manual says use of any fuse higher than 20 amps voids the warranty. > Could an exception be made if only one set of 25 amp fuses were installed? > > > > William > > > > > > PS: I am not sure fuses are required in a combiner with just two > strings. The SW275 module can withstand 16 amp external feed (from the max > fuse rating). A parallel module will output 8.94 times 1.56 or 13.95. This > is less than the 16 amps. This used to be allowed in earlier versions of > the code, I will have to look and see if it still is. > > > > Wm > > > > > > [image: Gradient Cap_mini] > Lic 773985 > millersolar.com <http://www.millersolar.com/> > 805-438-5600 > > > > *From:* RE-wrenches [mailto:[email protected]] *On > Behalf Of *Michael Kelly > *Sent:* Monday, October 06, 2014 3:10 PM > *To:* RE-wrenches > *Subject:* Re: [RE-wrenches] TL inverter with long DC Feeder > > > > Hi William, > > > > I wanted to let you know that currently, there is no bypass terminal to > allow for combining at the array in this series of inverters. We have > gotten a lot of feedback from customers that this is a required feature. > Working toward that, in the next few months, we will phase into production > an update that will include a bypass, but the existing stock does not have > the feature. > > > > I wanted to let you know so you could plan appropriately. > > > > Best, > > Mike > > > > *Michael Kelly* > > [image: Solectria_Yaskawa_signature_logo] <http://www.solectria.com/> > > HQ: 360 Merrimack Street, Bldg 9, Fl 2, Entrance I, Lawrence, MA 01843 USA > > O: +1 978-683-9700 x167 | F: +1 978-683-9702 > > *[email protected] <[email protected]>* | www.solectria.com > > > > *NOTICE:* This e-mail may contain confidential and/or privileged > information. If you are not the intended recipient, or an authorized > representative of the recipient, please be advised that you may not use, > copy or disclose its contents in part or in whole. If you have received > this message in error, please advise the sender by replying to this e-mail, > and delete the message. Thank you. > > > > *From:* RE-wrenches [mailto:[email protected] > <[email protected]>] *On Behalf Of *William Miller > *Sent:* Monday, October 6, 2014 14:40 > *To:* RE-wrenches > *Subject:* [RE-wrenches] TL inverter with long DC Feeder > > > > Wrenches: > > > > We are getting up to speed on using transformer-less inverters. I have > advocated long for the additional safety offered by these inverters but I > am realizing the trade-offs with the new technology: The implementation > gets more complicated with the requirement for PV wire, OCPD and > disconnecting means for plus and minus and plus providing Arc Flash rated > equipment. > > > > I am currently designing a system that will locate the PV about 400 feet > from the residence. The system will utilize 2 Solectria 5200 watt > inverters at the residence. I would like to provide disconnecting means > for the 4 strings at the array, in case of any needed service or > excavating. Preferably I’d like the disconnecting means to be deployable > by a lay person (i.e. the gardener). > > > > Finding an 8 pole, arc flash, 600 VDC rated disconnect is not easy. I > could install an Outback 8 circuit combiner with 8 touch-safe fuse > holders. The new combiners have had dead-fronts for a while now. The > gardener needs only to have a Philips screw driver to open this cover. Any > better ideas out there? > > > > Thanks, > > > > William > > > > > > [image: Gradient Cap_mini] > Lic 773985 > millersolar.com <http://www.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 > > > -- Chris Mason NABCEP Certified Solar PV Installer™ Solar Design Engineer Generac Generators Industrial technician www.cometsolar.com <http://www.cometenergysystems.com> 264.235.5670 869.662.5670 Skype: netconcepts
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