<html><body bgcolor="#FFFFFF"><div>That sounds right, which means that the existing wiring between the service disconnect and the transfer switch may also need to be evaluated since it will now have sources available at both ends. The rule applies to all bus bars and conductors "upstream" of the interconnection point as I understand it.<br><br>Jason Szumlanski</div><div>Fafco Solar</div><div><br>On Oct 12, 2010, at 6:25 AM, "Mark Frye" <<a href="mailto:markf@berkeleysolar.com">markf@berkeleysolar.com</a>> wrote:<br><br></div><div></div><blockquote type="cite"><div>
<div dir="ltr" align="left"><span class="171243404-12102010"><font color="#0000ff" size="2" face="Arial">It doesn't sound like you have a "supply side connection". It
sounds like you have a "load side connection" which is upstream of the transfer
switch but still downstream of the service disconnect.</font></span></div>
<div dir="ltr" align="left"><br><span lang="en-us"><font size="2" face="Arial">Mark
Frye</font></span> <br><span lang="en-us"><font size="2" face="Arial">Berkeley Solar
Electric Systems</font></span> <br><span lang="en-us"><font size="2" face="Arial">303
Redbud Way</font></span> <br><span lang="en-us"><font size="2" face="Arial">Nevada
City, CA 95959</font></span> <br><span lang="en-us"><font size="2" face="Arial">(530) 401-8024</font></span> <br><span lang="en-us"></span><a href="http://www.berkeleysolar.com/"><span lang="en-us"><u><font color="#0000ff" size="2" face="Arial">www.berkeleysolar.com</font></u></span></a><span lang="en-us"><font size="2" face="Arial"> </font></span> </div>
<div> </div><br>
<div dir="ltr" lang="en-us" class="OutlookMessageHeader" align="left">
<hr tabindex="-1">
<font size="2" face="Tahoma"><b>From:</b> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Dave
Palumbo<br><b>Sent:</b> Monday, October 11, 2010 9:15 PM<br><b>To:</b>
'RE-wrenches'<br><b>Subject:</b> Re: [RE-wrenches] Supply side connection to a
dedicated panel<br></font><br></div>
<div></div>
<div class="WordSection1">
<p class="MsoNormal">We are installing a 8kW grid tied PV system for a commercial
client. There is an auto start generator on the premises, therefore we
will be utilizing a supply side AC point of connection. Inverter is an SMA
SB8000. System owner plans on adding to system in the next few years. We are
designing for a total of 24kW of PV.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">We will install a 200A fused disconnect off the grid feed
(line side of the generator transfer switch). My plan is install a dedicated
breaker panel for the inverter 240VAC output(s). The SB8000 is rated at 29 Amps,
so a 40A DP breaker will do for the point of connection. This panel will
eventually have a total of (3) 40A DP breakers each with 8kW of inverter output.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">My question has to do with the interpretation of the 120
percent rule of the rating of the busbar in the panel. Do I need to use a 225
Amp rated panel with a downsized 150A main breaker? 225A busbar x 1.2 = 270 Amps
-150A MB = 120A total of inverter output allowed. Or, since this panel will only
be used for inverter AC point of connection, and not for loads, is it allowable
to label this panel as a “Dedicated Panel – connect no loads”. If that is the
case we could use a 200A panel, or even a 150Amp panel. A local electrician
proposed this “dedicated panel” to avoid the larger load center panel. I cannot
find any mention of “dedicated panel” in the NEC. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I think what I am proposing follows 690.64. Any opinions, or
advice would be appreciated.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Dave Palumbo<o:p></o:p></p>
<p class="MsoNormal">Independent Power LLC <o:p></o:p></p>
<p class="MsoNormal"><i><a href="http://www.independentpowerllc.com">www.independentpowerllc.com</a> <o:p></o:p></i></p>
<p class="MsoNormal">NABCEP Certified PV Installer<o:p></o:p></p>
<p class="MsoNormal">Vermont Solar Partner<o:p></o:p></p>
<p class="MsoNormal">802.888.7194 <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p></div>
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