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Al,<br>
<br>
How about a 15-amp single-pole breaker for power line carrier
communications equipment to talk to the inverters?<br>
Technically, I think either way they are loads and that changes
everything. But in my opinion they are minor and should be allowed
without considering the sum of all sources.<br>
<br>
Kent Osterberg<br>
Blue Mountain Solar<br>
<br>
<br>
Al Frishman wrote:
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<div class="WordSection1">
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">Is
a monitoring system installed in the Load Center to measure the
cumulative kWh’s of the inverter’s considered a load? <o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">The
type of monitoring device I am talking about has CT’s that go around
the conductors and the Voltage ref is taken by attaching conductors to
each phase, the Neutral and the ground bar. The digital Meter has a
3-pole 5A breaker in it so the conductors in the load center can be
connected to lugs on the bus bar directly.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><i><span
style="font-size: 10.5pt; font-family: "Helvetica","sans-serif";">Al
Frishman</span></i><span
style="font-size: 13.5pt; font-family: "Helvetica","sans-serif";"><br>
</span><span
style="font-size: 13.5pt; font-family: "'Microsoft Sans Serif'"; color: rgb(3, 1, 0);">Aeon</span><span
style="font-size: 13.5pt; font-family: "'Microsoft Sans Serif'"; color: rgb(255, 151, 0);">Solar</span><span
style="font-size: 13.5pt; font-family: "Helvetica","sans-serif";"><o:p></o:p></span></p>
<p class="MsoNormal"><i><span
style="font-size: 10.5pt; font-family: "Helvetica","sans-serif";">(917)
699-6641 - cell</span></i><span
style="font-size: 10.5pt; font-family: "Helvetica","sans-serif";"><br>
</span><i><span
style="font-size: 10.5pt; font-family: "Helvetica","sans-serif";">(888)
460-2867</span></i><span
style="font-size: 10.5pt; font-family: "Helvetica","sans-serif";"><br>
</span><i><span
style="font-size: 10.5pt; font-family: "Helvetica","sans-serif";"><a
moz-do-not-send="true" href="http://www.aeonsolar.com/">www.aeonsolar.com</a></span></i><span
style="font-size: 13.5pt; font-family: "Helvetica","sans-serif";"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-align: center;" align="center"><i><span
style="font-size: 14pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"><o:p> </o:p></span></i></p>
</div>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<div>
<div
style="border-style: solid none none; border-color: rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color; border-width: 1pt medium medium; padding: 3pt 0in 0in;">
<p class="MsoNormal"><b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: windowtext;">From:</span></b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: windowtext;">
<a class="moz-txt-link-abbreviated" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[<a class="moz-txt-link-freetext" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Jason
Szumlanski<br>
<b>Sent:</b> Wednesday, March 30, 2011 8:18 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] sizing a sub-panel used to
combinemultipleinverter outputs<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">Another
key is to remember that this discussion also applies to the conductor
between the main panel and subpanel. In a large PV system, this could
result in a pretty large wire between the two panels, and a significant
cost that is often overlooked. In some cases it makes sense to locate
the subpanel close to the main panel and run multiple sets of smaller
wires from the inverters to the subpanel.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">And
because the calculation is based on the first OC protection connected
to the inverters, adding a main breaker (theoretically 80A in this
example) in the subpanel doesn’t change things. Even though this wire
would be theoretically protected by an 80A breaker at each end, you
can’t size the wire for 160A / 1.2 = 133.3A. You have to size for
180A/1.2 = 150A. (not that it makes much of a difference in this
example, but it still must be considered)<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">At
least that’s how I understand it…<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><span
style="font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">Jason
Szumlanski<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">Fafco
Solar</span><span
style="font-size: 4pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);">
<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
</div>
<p class="MsoNormal"><span
style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(31, 73, 125);"><o:p> </o:p></span></p>
<div>
<div
style="border-style: solid none none; border-color: rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color; border-width: 1pt medium medium; padding: 3pt 0in 0in;">
<p class="MsoNormal"><b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: windowtext;">From:</span></b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: windowtext;">
<a class="moz-txt-link-abbreviated" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[<a class="moz-txt-link-freetext" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Mark
Frye<br>
<b>Sent:</b> Wednesday, March 30, 2011 1:33 AM<br>
<b>To:</b> 'RE-wrenches'<br>
<b>Subject:</b> Re: [RE-wrenches] sizing a sub-panel used to
combinemultipleinverter outputs<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span
style="font-size: 10pt; font-family: "Arial","sans-serif"; color: blue;">Opps!</span><o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><span
style="font-size: 10pt; font-family: "Arial","sans-serif"; color: blue;">My
bad, I was thinking of a single phase system, not the three phase
system shown in the article.</span><o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><span
style="font-size: 10pt; font-family: "Arial","sans-serif"; color: blue;">For
the three phase system Kent is correct in counting 180A of supply per
bar.</span><o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><span
style="font-size: 10pt; font-family: "Arial","sans-serif";">Mark Frye</span>
<br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">Berkeley
Solar Electric Systems</span> <br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">303
Redbud Way</span> <br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">Nevada
City, CA 95959</span> <br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">(530)
401-8024</span> <br>
<a moz-do-not-send="true" href="http://www.berkeleysolar.com/"><span
style="font-size: 10pt; font-family: "Arial","sans-serif";">www.berkeleysolar.com</span></a><span
style="font-size: 10pt; font-family: "Arial","sans-serif";"> </span> <o:p></o:p></p>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div class="MsoNormal" style="text-align: center;" align="center">
<hr align="center" size="2" width="100%"></div>
<p class="MsoNormal" style="margin-bottom: 12pt;"><b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif";">From:</span></b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif";">
<a class="moz-txt-link-abbreviated" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[<a class="moz-txt-link-freetext" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Mark
Frye<br>
<b>Sent:</b> Tuesday, March 29, 2011 10:17 PM<br>
<b>To:</b> 'RE-wrenches'<br>
<b>Subject:</b> Re: [RE-wrenches] sizing a sub-panel used to combine
multipleinverter outputs</span><o:p></o:p></p>
<p class="MsoNormal"><span
style="font-size: 10pt; font-family: "Arial","sans-serif"; color: blue;">I
think Kent and I agree. For the case where the subpanel is not
dedicated a PV sub-panel he is calculating for 2 - 50A breakers and I
calculated for 3 - 50A breakers.</span><o:p></o:p></p>
<p class="MsoNormal"><br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">Mark
Frye</span> <br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">Berkeley
Solar Electric Systems</span> <br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">303
Redbud Way</span> <br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">Nevada
City, CA 95959</span> <br>
<span style="font-size: 10pt; font-family: "Arial","sans-serif";">(530)
401-8024</span> <br>
<a moz-do-not-send="true" href="http://www.berkeleysolar.com/"><span
style="font-size: 10pt; font-family: "Arial","sans-serif";">www.berkeleysolar.com</span></a><span
style="font-size: 10pt; font-family: "Arial","sans-serif";"> </span> <o:p></o:p></p>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div class="MsoNormal" style="text-align: center;" align="center">
<hr align="center" size="2" width="100%"></div>
<p class="MsoNormal" style="margin-bottom: 12pt;"><b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif";">From:</span></b><span
style="font-size: 10pt; font-family: "Tahoma","sans-serif";">
<a class="moz-txt-link-abbreviated" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[<a class="moz-txt-link-freetext" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Kent
Osterberg<br>
<b>Sent:</b> Tuesday, March 29, 2011 9:26 PM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] sizing a sub-panel used to combine
multiple inverter outputs</span><o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom: 12pt;">Per 705.12(D) the
sub-panel could be any distribution equipment on the premises. So the
question becomes: is the sub-panel capable of supplying branch circuits
or feeder loads? If yes, then the sum of the breakers (potentially)
feeding the bus is 180 amps so a 150-amp rating is required and the
inverters would have to feed the opposite end of the bus bars. If no,
the code is not clear on the requirement, but obviously the 80-amp
breaker in the main panel limits the maximum current flowing through
the sub-panel. <br>
<br>
Kent Osterberg<br>
Blue Mountain Solar<o:p></o:p></p>
</div>
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