Right, Kent, but 690.4(D) does require the use of products ³identified and listed for the application.² So, for example, UL-listed combiner boxes are required per NEC 2008, whereas integrators could previously site build combiners using UL-listed parts. The appropriate listing for a PV combiner, everyone agrees, is UL1741. This code article lists most major components in a PV system, but not discos. I¹m simply wondering if there is some activity I am unaware of seeking to add dc discos to this list or to the UL1741 standard. Just curious.
On 1/11/10 6:27 PM, "Kent Osterberg" <k...@coveoregon.com> wrote: > David, > > The NEC doesn't require UL listing. The most appropriate section of the code > about this is Article 110, Requirements for Electrical Installations, it > requires equipment to be approved. In many jurisdictions, such as Oregon, > that means evaluated and approved by a testing lab such as UL. > > Kent Osterberg > Blue Mountain Solar, Inc. > > > David Brearley wrote: >> Re: [RE-wrenches] Square D DC disconnects Thanks, Bill. >> >> Glad to hear you think the HU series is still a good option. >> >> When I was making the rounds at SPI, I stopped by the Eaton booth and got the >> sense that they were gunning for Square D. They made light of Square D¹s >> self-certification of the HU series discos. The rep also made a statement >> about the new Eaton dc discos being the only ones designed to meet UL1741 >> requirements. When I got home, the first thing I looked up was 690.4(D). This >> doesn¹t say anything about dc disconnects needing to be listed to some >> special PV standard. >> >> Is there a movement in this direction? Is there a UL1741 standard for dc >> discos that is somehow different that the standard used for other dc >> disconnects? >> >> Best, >> >> David >> >> On 1/11/10 5:28 PM, "Bill Brooks" <billbroo...@yahoo.com> wrote: >> >> >>> David and Kirpal, >>> >>> It is ultimately up to the AHJ whether or not they accept the >>> Schneider/Square D self certification. That is a judgment call the installer >>> needs to clear with the AHJ. That being said, having Square D behind the >>> rating of a switch is a whole lot more than any one of the smaller companies >>> making equipment for the PV industry. >>> >>> I will continue to use the 30, 60, and 100-amp versions in the way >>> recommended by the manufacturer because it is a huge saving in cost and they >>> are well made switches. I will also check with the local AHJ before >>> installing them in case they are not going to pass it. You have to remember >>> you are working with one of the largest electrical suppliers in the world. >>> They have a huge reputation with local jurisdictions. >>> >>> Eaton has been in the process of trying to make a big deal out of this issue >>> since they want a piece of the market. Fortunately, they are starting to >>> build products specifically for the PV industry, which I applaud. However, >>> they need to be given a hard time for the way they have tried to imply that >>> all Square D switches are not properly listed. They won¹t admit to that >>> because they would end up in a legal battle, but that is essentially what >>> they have been doing. Square D still has the largest selection of dc-rated >>> equipment on the market. Eaton has a long way to go. >>> >>> In a recent project that I reviewed, the engineer pulled the Square D >>> 400-amp disconnect and replaced it with an Eaton disconnect at the >>> insistence of the Eaton rep. The Eaton product was not properly rated or >>> listed for the voltage while the Square D product was. This is the insanity >>> that needs to stop. >>> >>> Bill. >>> >>> >>> >>> From: re-wrenches-boun...@lists.re-wrenches.org >>> [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of David >>> Brearley >>> Sent: Monday, January 11, 2010 11:39 AM >>> To: RE-wrenches >>> Subject: Re: [RE-wrenches] Square D DC disconnects >>> >>> Kirpal, >>> >>> Have you checked out the SolarBOS disconnecting combiners? Their 28A version >>> might be ideal for large resi or small commercial applications. For larger >>> projects, Blue Oak PV Products and AMtec Solar also have disconnecting >>> combiners. >>> >>> Thanks for sharing the updated Square D tech note. I had no idea that the >>> Square D HU Series disconnects were not UL-listed when used as described in >>> the older tech notes. The fact that this is not a UL-listed use of the heavy >>> duty safety switch, pretty much means that it is not an option for >>> integrators. As far as I know, there is no other product that is listed for >>> this use. >>> >>> David Brearley, Senior Technical Editor >>> SolarPro magazine >>> NABCEP Certified PV Installer >>> david.brear...@solarprofessional.com >>> >>> >>> On 1/9/10 4:14 PM, "Kirpal Khalsa" <solarwo...@gmail.com> wrote: >>> >>>> Hi All...... >>>> >>> >>> I recently came across a revised technical bulletin from square D ( >>> http://ecatalog.squared.com/pubs/Electrical%20Distribution/Safety%20Switches >>> /Heavy%20Duty/3110DB0401.pdf )......we have for years been using the Square >>> D DC Disconnect of various amperages (30, 60, 100) as disconnects leading >>> upto the inverter from the array.....we have frequently wired one string to >>> each of the three poles of the disconnect......we have had this >>> configuration inspected by inspectors regularly with approval >>> everytime......this new revision of the document from Square D shows this is >>> no longer a UL listed method.....they are now stating in this document that >>> they are "self certifying" this technique.......have any of you come across >>> this or know why Square D has back tracked? >>> >>> Something else I noticed is that they have raised the amperage rating on the >>> 30A disconncect per pole by 2 amps from 18 to 20 which is good especially >>> when using higher amperage modules like Evergreen ES-A series which would >>> not have ben allowed to use the 30A disconnect as the short circuit current >>> rating was too high for the derated poles. >>> >>> This is not a huge concern as more and more of the inverters we are using >>> these days have an appropriate disconnect included with the inverter >>> negating the need for an additional stand alone disconnect. >>> >>> On a side note............Are there any other manufacturers making listed >>> muiti pole DC disconnects in which each pole can handle one string? Also >>> there is definately a need for roof mounted multi string (1-4 strings) >>> combiner boxes with integrated DC disconnects for residential applications >>> that have a reasonable price.......any one know if any? >>> >>> >>> >>> >>> >>> >>> >> >> >> >> >> >> >> >> >> _______________________________________________ >> 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 <http://www.re-wrenches.org/etiquette.htm> >> >> Check out participant bios: >> www.members.re-wrenches.org <http://www.members.re-wrenches.org> >> >> >> >> >> >> >> >> No virus found in this incoming message. >> Checked by AVG - www.avg.com <http://www.avg.com> >> Version: 9.0.725 / Virus Database: 270.14.135/2615 - Release Date: 01/11/10 >> 11:35:00 >> >> > > > _______________________________________________ > 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 > David Brearley, Senior Technical Editor SolarPro magazine NABCEP Certified PV Installer david.brear...@solarprofessional.com Direct: 541.261.6545 Fax: 541.512.0343 Visit our Web site at solarprofessional.com (Sample copy available for download at: solarprofessional.com/sample)
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