Thanks, Dave. Anyone have clarification on what exact marks to look for in "PV Wire?"
For example, the cables I see on a batch of Suntechs I have in the shop are listed as "H+S RADOX SMART cable 4.0 mm" on the spec sheet but the only listing I see on the wire themselves is RHH/RHW-2. NEC Table 310.13(1) doesn't seem to mention PV Wire. Thanks again for all your help. Best, August -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Dave Click Sent: Friday, December 10, 2010 1:11 PM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] Tranformless inverter I believe it's just: Fusing on the +/- disconnects break both + and - Need your modules to use PV wire labeling per 690.35(F) Square D discos are UL'd for ungrounded systems- and I just noticed that there's a June 2010 revision of the Square D disconnect guide. A bit of clarification since the 9/09 edition I had. http://ecatalog.squared.com/pubs/Electrical%20Distribution/Safety%20Switches/Solar%20Disconnect%20Switches/3110DB0401.pdf August Goers wrote: > Hi Bill and Wrenches - > > For ungrounded arrays what specific fusing and or DC disconnect > requirements are needed compared to grounded arrays? > > I'm trying to sort through the code but nothing is popping out at me > besides what was already mentioned about needing to disconnect both the > positive and negative lines on the DC side. In SMA's case I'm guessing > that their new transformerless inverters with integrated DC disconnects > and fuses may already take of all the requirements? > > Best, > > August > > August Goers > > Luminalt Energy Corporation > > 1320 Potrero Avenue > > San Francisco, CA 94110 > > m: 415.559.1525 > > o: 415.641.4000 > > aug...@luminalt.com <mailto:aug...@luminalt.com> > > *From:*re-wrenches-boun...@lists.re-wrenches.org > <mailto:re-wrenches-boun...@lists.re-wrenches.org> > [mailto:re-wrenches-boun...@lists.re-wrenches.org > <mailto:re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf Of *Bill > Brooks > *Sent:* Friday, October 01, 2010 8:29 AM > *To:* 'RE-wrenches' > *Subject:* Re: [RE-wrenches] Tranformless inverter > > All, > > Transformerless inverters are simply a subset of ungrounded or > resistively grounded PV systems covered by the NEC in 690.35 since the > 2005 code cycle. Power-One has been marketing their ungrounded inverter > in the U.S. for several years now. It was listed by CSA. The > requirements for ungrounded systems in 690.35 are as follows: > > *"Photovoltaic power systems shall be permitted to operate with > ungrounded photovoltaic source and output circuits where the system > complies with 690.35(A) through 690.35(G). > > -*(A) Disconnects. *All photovoltaic source and output circuit > conductors shall have disconnects complying with 690, Part III. > > -*(B) Overcurrent Protection. *All photovoltaic source and output > circuit conductors shall have overcurrent protection complying with 690.9. > > -*(C) Ground-Fault Protection. *All photovoltaic source and output > circuits shall be provided with a ground-fault protection device or > system that complies with (1) through (3): > > *(1) Detects a ground fault. > > *(2) Indicates that a ground fault has occurred > > *(3) Automatically disconnects all conductors or causes the inverter or > charge controller connected to the faulted circuit to automatically > cease supplying power to output circuits. > > -*(D) *The photovoltaic source and output conductors shall consist of > the following: > > -(1) Nonmetallic jacketed multiconductor cables > > -(2) Conductors installed in raceways, or > > -(3) Conductors listed and identified as Photovoltaic (PV) Wire > installed as exposed, single conductors. > > -*(E) *The photovoltaic power system direct-current circuits shall be > permitted to be used with ungrounded battery systems complying with > 690.71(G). > > -*(F) *The photovoltaic power source shall be labeled with the following > warning at each junction box, combiner box, disconnect, and device where > the ungrounded circuits may be exposed during service: > > WARNING > > ELECTRIC SHOCK HAZARD > > THE DC CIRCUIT CONDUCTORS OF THIS > > PHOTOVOLTAIC POWER SYSTEM ARE > > UNGROUNDED AND MAY BE ENERGIZED > > WITH RESPECT TO GROUND DUE TO > > LEAKAGE PATHS AND/OR GROUND FAULTS. > > -*(G) *The inverters or charge controllers used in systems with > ungrounded photovoltaic source and output circuits shall be listed for > the purpose. > > We now have several products newly on the market to include on the list > such as the SMA and Exeltech products. Ungrounding the array requires > additional fusing and disconnects, but the most significant difference > is that the module wiring and all external cable must be PV Wire/Cable. > Therefore only modules with PV Wire/Cable can be used in these systems. > You must confirm from the manufacturer that they have made the switch. > Hopefully all manufacturers will be installing PV Wire/Cable soon so > that this will not be a problem anymore. > > It is a good call to use up your USE-2 and order PV Wire/Cable from now > on. > > Bill. > > *From:*re-wrenches-boun...@lists.re-wrenches.org > <mailto:re-wrenches-boun...@lists.re-wrenches.org> > [mailto:re-wrenches-boun...@lists.re-wrenches.org > <mailto:re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf Of > *Exeltech > *Sent:* Friday, October 01, 2010 6:39 AM > *To:* RE-wrenches > *Subject:* Re: [RE-wrenches] Tranformless inverter > > Transformerless grid-tie inverters are permitted under the National > Electric Code as of 2008. The Nationally Recognized Testing Laboratories > (UL, ETL/Intertek, CSA, etc.) took a while to develop the testing > procedures for testing to UL1741, which was the basis for most of the > delay. > > SMA isn't the only company with transformerless grid-tie inverters. I > know of one American manufacturer with transformerless models on the > market as well. > > Transformerless inverters are smaller, much lighter, and tend to be more > efficient than transformer-based units. No transformer also means lower > product cost, and less shipping expense. Win-win-win. > > > Dan > > > --- On *Fri, 10/1/10, Drake /<drake.chamber...@redwoodalliance.org > <mailto:drake.chamber...@redwoodalliance.org>>/* wrote: > > > From: Drake <drake.chamber...@redwoodalliance.org > <mailto:drake.chamber...@redwoodalliance.org>> > Subject: Re: [RE-wrenches] Tranformless inverter > To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org > <mailto:re-wrenches@lists.re-wrenches.org>> > Date: Friday, October 1, 2010, 6:58 AM > > I also received this advertisement. Previously I had investigated the > smaller SMA transformerless inverters, and was told that this type would > not be allowed in the US until the 2011 code. Has the ban been lifted? > > > > At 12:52 AM 9/29/2010, you wrote: > > Wrenches: > > I received an advertisement from a distributor that SMA is now shipping > 8, 9 and 10 KW transformerless inverters. Don't these require double > insulated PV wiring and no connection to ground on the AC side? It's > been too long since this subject last crossed my desk and I want to > refresh my memory on the specifics. > > William Miller > > > _Please note new e-mail address and domain: > > _William Miller > Miller Solar > Voice :805-438-5600 > email: will...@millersolar.com <mailto:will...@millersolar.com> > http://millersolar.com <http://millersolar.com/> > License No. C-10-773985 > > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options& settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules& etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
