Hi Dan Can you provide any documentation on this?
Thanks Jay Peltz power. Sent from my iPhone > On Jan 28, 2016, at 8:52 PM, <d...@energysolarnow.com> > <d...@energysolarnow.com> wrote: > > While Brian T. is correct that fusing is not required for string-to-string > overcurrent protection with two strings into two channels, there is another > reason to require fusing. > Transformerless inverters like Fronius Primo have no transformer to provide > AC-DC isolation, so a ground fault can allow excessive AC current from AC > neutral to enter the DC side and fry inverter components. Transformerless > inverters need fuses on both DC positive and DC negative legs to protect the > inverter in case of ground fault. > This is why both DC+ and DC- are switched and PV wire is required for DC > connections-- to protect the inverters, not just the PV modules. > This is also why SMA, for example, no longer has any fuses in their > disconnect switches but requires a separate fused DC combiner box with fuses > for both positive and negative circuits. > I have had inverter damage with another inverter brand that only had fuses > for the DC+. They now provide fuses on both legs. > > Don Barch > Energy Solar > > Date: Wed, 27 Jan 2016 17:31:22 -0800 > From: Brian Teitelbaum <bteitelb...@aeesolar.com> > To: RE-wrenches <re-wrenches@lists.re-wrenches.org> > Subject: Re: [RE-wrenches] fusing requirement for 4 strings run to a > Inverter with 2 MPPT's > Message-ID: <7b344022a97655195ced29e564a31...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Al, > > > > As long as you only have a max of two strings going into each of the > separate MPPT channels, no string fusing is needed. So with four strings, > two on each MPPT input channel in the inverter, no string fusing is needed. > This is one of the big advantages to having multiple MPPT channels in GT > inverters. > > > > No need to run separate conduits either. All four PV string circuits can be > run in a single conduit, as long as the conduit is properly sized for wire > fill, of course. > > > > > > Brian Teitelbaum > > AEE Solar > > > > > > *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On > Behalf Of *Allen Frishman > *Sent:* Wednesday, January 27, 2016 6:12 AM > *To:* re-wrenches@lists.re-wrenches.org > *Subject:* [RE-wrenches] fusing requirement for 4 strings run to a Inverter > with 2 MPPT's > > > > Wrenchers, > > What is the requirement for fusing 2 strings per MPPT? Specifically for > an inverter like the Fronius Primo that has no integrated fuses. If you > run 2 strings to each MPPT do you need to fuse each string? In this case > there is a total of 4 strings which would need to be fused if using a > single mppt. > > > > If the home runs are run in separate conduits from the array to limit the > strings in the conduit to 2 per you still have all 4 strings together in > the inverter. > > > > All thoughts and feedback are appreciated. > > *Al Frishman* > AeonSolar > > *(917) 699-6641 <%28917%29%20699-6641> - cell* > *(888) 460-2867 <%28888%29%20460-2867>* > *www.aeonsolar.com <http://www.aeonsolar.com/>* > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20160127/87113140/attachment-0001.htm> > > > _______________________________________________ > 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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