<p dir="ltr">Gary,</p>
<p dir="ltr">I thought most inverters share power. So if the inverter has a 60A transfer switch and all of that is needed for loads then none for charging and as load demand decreases, charging increases. </p>
<p dir="ltr">Larry Liesner<br>
Elektron Solar</p>
<div class="gmail_quote">On Feb 28, 2013 11:33 AM, <<a href="mailto:gary@icarussolarservices.com">gary@icarussolarservices.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><p>Garrison, et al:</p>
<p> </p>
<p>Another consideration when sizing the POCC OCPD (either load side or supply
side) is charging current when the grid power returns and the battery bank is
near the LBCO voltage. </p>
<p> </p>
<p>Bulk charging current and AC pass-through current both must be considered
when sizing the POCC OCPD.</p>
<p> </p>
<p>Regards,</p>
<p> </p>
<p>Gary Willett</p>
<p>Icarus Solar<br><br>On Thu, 28 Feb 2013 10:04:51 -0600, Garrison Riegel
<<a href="mailto:garrison@solarserviceinc.com" target="_blank">garrison@solarserviceinc.com</a>> wrote:<br></p>
<blockquote style="BORDER-LEFT:rgb(0,0,0) 2px solid;PADDING-LEFT:5px;PADDING-RIGHT:0px;MARGIN-LEFT:5px;MARGIN-RIGHT:0px" dir="ltr">
<div><div>
<p class="MsoNormal"><span style="COLOR:#1f497d">Great point Dave. It crossed my mind that it was technically
possible, but figured since I would be removing loads off the main panel it was
highly unlikely. Thanks for the code reference. I’ll go load side, and be
prepared for some discussion.
<p> </p></span></p>
<p class="MsoNormal"><span style="COLOR:#1f497d">
<p> </p></span></p>
<p class="MsoNormal"><span style="COLOR:#1f497d">Thanks,
<p> </p></span></p>
<p class="MsoNormal"><span style="COLOR:#1f497d">
<p> </p></span></p>
<p class="MsoNormal"><span style="COLOR:#1f497d">Garrison
<p> </p></span></p>
<p class="MsoNormal"><span style="COLOR:#1f497d">
<p> </p></span></p>
<p class="MsoNormal"><span style="COLOR:#1f497d">
<p> </p></span></p>
<div>
<div style="BORDER-BOTTOM:medium none;BORDER-LEFT:medium none;PADDING-BOTTOM:0in;PADDING-LEFT:0in;PADDING-RIGHT:0in;BORDER-TOP:#b5c4df 1pt solid;BORDER-RIGHT:medium none;PADDING-TOP:3pt">
<p class="MsoNormal"><b><span>From:</span></b><span> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>
[mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Dave
Click<br><b>Sent:</b> Thursday, February 28, 2013 9:21 AM<br><b>To:</b>
<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a><br><b>Subject:</b> Re: [RE-wrenches] Conductor
Sizing for Supply Side Connection
<p> </p></span></p></div></div>
<p class="MsoNormal">
</p><p> </p>
<p class="MsoNormal">As a note, supply side
connections have an extra complication with battery backup systems. With a
regular GT inverter you're just pushing current into that interconnection point
and you can work out easily that you won't have any overcurrent issues unless
you made a big mistake and your inverter output exceeds the rating of your
service conductors. However, with a battery system you're also potentially
pulling current from that point. Before the battery inverter is installed your
main breaker protects your service conductors, but if the inverter is pulling in
60A and the main breaker is also operating near its capacity, you could have
>240A running over 200A service conductors with no breakers tripping. You
would overwhelm the capacity of the service [230.23(A)] and no breakers would
trip. You could fix this by replacing your service conductors back to the
transformer (I'm just saying that it's an option) or downsizing the main
breaker, and at that point you're probably better off just making it a load side
connection. I'd go load side and argue with the AHJ to use the 2011 update
mentioned earlier.<br><br>Dave
</p><p> </p>
<div>
<p class="MsoNormal">On 2013/2/28 9:55, Garrison Riegel wrote:
</p><p> </p></div>
<blockquote style="MARGIN-TOP:5pt;MARGIN-BOTTOM:5pt">
<p class="MsoNormal"><span style="COLOR:#1f497d">Allen,</span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d">The benefit I see would be to allow for a code compliant load side
connection on a 200A panel with a 200A MB, where the AHJ is on the 2008 NEC or
older and will not listen to your good logic. I don’t think this would
always be the best option, but if backup loads and inverter output were less
than 32A then a 40A OCPD in the main panel should be fine? Since it sounds
like the 60A breaker in the main panel is not a safety issue, but a design
consideration, I suppose I would just prefer flexibility when possible.</span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d">That said, this AHJ is on the 2008, and the loads will be less than
30A, but based on this conversation I plan to go with a 60A and try to convince
the AHJ that it will be code compliant in their future!</span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d">Thanks,</span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d">Garrison</span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<div>
<div style="BORDER-BOTTOM:medium none;BORDER-LEFT:medium none;PADDING-BOTTOM:0in;PADDING-LEFT:0in;PADDING-RIGHT:0in;BORDER-TOP:#b5c4df 1pt solid;BORDER-RIGHT:medium none;PADDING-TOP:3pt">
<p class="MsoNormal"><b><span>From:</span></b><span> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a> [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of
</b>Allan Sindelar<br><b>Sent:</b> Thursday, February 28, 2013 8:14
AM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Conductor
Sizing for Supply Side Connection</span>
</p><p> </p></div></div>
<p class="MsoNormal">
</p><p> </p>
<div>
<p class="MsoNormal">Garrison,<br>I don't
know why it's not listed as 60A max, but my own internal logic would ask why it
should be. The only benefit I could see for using smaller than a 60A breaker
would be to allow use of #8 conductors (allowed with a 40A or 50A breaker)
instead of the #6 necessary with a 60A breaker. And of course, you could use a
40A breaker with #6 conductors, so theoretically it would be fine. I just fail
to see any benefit to doing so.<br>Allan
</p><p> </p>
<div>
<p class="MsoNormal"><b>Allan Sindelar</b><br><span style="FONT-SIZE:10pt"><a href="mailto:Allan@positiveenergysolar.com" target="_blank"><span style="COLOR:#000099">Allan@positiveenergysolar.com</span></a></span><br><span style="FONT-SIZE:10pt">NABCEP Certified
Photovoltaic Installer<br>NABCEP Certified Technical Sales Professional<br>New
Mexico EE98J Journeyman Electrician<br>Founder and Chief Technology
Officer<br><b>Positive Energy, Inc.</b><br>3209 Richards Lane (note new
address)<br>Santa Fe, New Mexico 87507<br><b><a href="tel:505%20424-1112" value="+15054241112" target="_blank">505 424-1112</a></b><br><a href="http://www.positiveenergysolar.com/" target="_blank">www.positiveenergysolar.com</a></span>
</p><p> </p>
<p class="MsoNormal">
</p><p> </p>
<p class="MsoNormal">
</p><p> </p></div>
<p class="MsoNormal">On 2/28/2013 6:27 AM, Garrison Riegel wrote:
</p><p> </p></div>
<blockquote style="MARGIN-TOP:5pt;MARGIN-BOTTOM:5pt">
<p class="MsoNormal"><span style="COLOR:#1f497d">Thanks Allen for clarifying why a 60A is required. I was
wondering. The spec does list a surge current of 9000W so I thought that may
be the rationale, but even that would only require a 50A, and since this surge
occurs during ‘stand-alone mode’ it didn’t seem to apply to the OCPD at
the main panel. Your explanation makes more sense, but I wonder why then they
don’t list the AC input breaker size as 60A <i>max</i>. If you have few
backup loads, and are not on the 2011 NEC, a 40A could theoretically be
fine?</span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d">Thanks all for your thoughts, much appreciated.</span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d">Garrison</span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<p class="MsoNormal"><span style="COLOR:#1f497d"> </span>
</p><p> </p>
<div>
<div style="BORDER-BOTTOM:medium none;BORDER-LEFT:medium none;PADDING-BOTTOM:0in;PADDING-LEFT:0in;PADDING-RIGHT:0in;BORDER-TOP:#b5c4df 1pt solid;BORDER-RIGHT:medium none;PADDING-TOP:3pt">
<p class="MsoNormal"><b><span>From:</span></b><span> <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a> [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of
</b>Allan Sindelar<br><b>Sent:</b> Wednesday, February 27, 2013 6:08
PM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] Conductor
Sizing for Supply Side Connection</span>
</p><p> </p></div></div>
<p class="MsoNormal">
</p><p> </p>
<div>
<p class="MsoNormal">August,<br>The 60A
breaker is intended to allow grid power to pass through to the loads in excess
of the inverter's stand-alone output. The point of 705.12 (moved in the 2011 NEC
from 690.64 (B)(2)) is to differentiate between load pass-through current and
sell current. The amount of current fed into the grid is (4500/230 =) 19.56A,
while the amount that can be taken from the grid and passed through to the load
is much greater. If you were limited to a 40A breaker in order to maintain 120%
of a 200A main bus, you'd be prone to nuisance trips under large cumulative
loads.<br><br>Allan
</p><p> </p>
<div>
<p class="MsoNormal"><b>Allan Sindelar</b><br><span style="FONT-SIZE:10pt"><a href="mailto:Allan@positiveenergysolar.com" target="_blank"><span style="COLOR:#000099">Allan@positiveenergysolar.com</span></a></span><br><span style="FONT-SIZE:10pt">NABCEP Certified
Photovoltaic Installer<br>NABCEP Certified Technical Sales Professional<br>New
Mexico EE98J Journeyman Electrician<br>Founder and Chief Technology
Officer<br><b>Positive Energy, Inc.</b><br>3209 Richards Lane (note new
address)<br>Santa Fe, New Mexico 87507<br><b><a href="tel:505%20424-1112" value="+15054241112" target="_blank">505 424-1112</a></b><br><a href="http://www.positiveenergysolar.com/" target="_blank">www.positiveenergysolar.com</a></span>
</p><p> </p>
<p class="MsoNormal">
</p><p> </p>
<p class="MsoNormal">
</p><p> </p></div></div>
<blockquote style="MARGIN-TOP:5pt;MARGIN-BOTTOM:5pt"><pre> <p> </p></pre></blockquote>
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