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<title>Re: [RE-wrenches] Square D DC disconnects</title>
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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>David and Kirpal,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>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. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>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.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>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 won’t 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. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>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.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Bill.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>David
Brearley<br>
<b>Sent:</b> Monday, January 11, 2010 11:39 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] Square D DC disconnects<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'>Kirpal,<br>
<br>
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.<br>
<br>
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. <br>
<br>
David Brearley, Senior Technical Editor<br>
<i>SolarPro</i> magazine <br>
NABCEP Certified PV Installer ™<br>
<a href="david.brearley@solarprofessional.com">david.brearley@solarprofessional.com</a><br>
<br>
<br>
On 1/9/10 4:14 PM, "Kirpal Khalsa" <<a href="solarworks@gmail.com">solarworks@gmail.com</a>>
wrote:</span><o:p></o:p></p>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Hi
All......</span><o:p></o:p></p>
</blockquote>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> </span><o:p></o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>I
recently came across a revised technical bulletin from square D ( <a
href="http://ecatalog.squared.com/pubs/Electrical%20Distribution/Safety%20Switches/Heavy%20Duty/3110DB0401.pdf">http://ecatalog.squared.com/pubs/Electrical%20Distribution/Safety%20Switches/Heavy%20Duty/3110DB0401.pdf</a> )......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? </span><o:p></o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> </span><o:p></o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>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. <br>
<br>
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. </span><o:p></o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <br>
On a side note............Are there any other manufacturers making <u>listed</u>
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?<br>
<br>
</span><o:p></o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif"'><br>
<br>
</span><o:p></o:p></p>
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