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Here is a wild idea. If you look at the Enphase inverter
systems, several inverters connect together in parallel before going to
an overcurrent device. <br><br>
In all cases, the point of connection to a utility system must be at a
dedicated breaker. If there were multiple string inverters that
would connect to one breaker, why not just use a junction box, instead of
a combiner panel? You could put in an AC disconnect for each
inverter, if it didn't come with one. <br><br>
The wiring would need to be sized for the combined output of the multiple
inverters, which in many cases wouldn't be an issue.<br><br>
Drake <br><br>
<br><br>
At 12:36 AM 1/13/2010, you wrote:<br>
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Andrew,<br>
<br>
It does not exist. We tried like crazy to get it into the 2011 NEC, but
to no avail. At the last second the proposal was put on hold until the
2014 NEC. Major bummer. For now it can only be done with AHJ approval.
Many allow it but it is not in the NEC. Alternatively you must use the
sum of supply breakers no greater than 120%. Much more restrictive.<br>
<br>
Bill.<br>
<br>
<b>From:</b> re-wrenches-bounces@lists.re-wrenches.org
[<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" eudora="autourl">
mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of
</b>Andrew Truitt<br>
<b>Sent:</b> Tuesday, January 12, 2010 10:57 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> [RE-wrenches] Solar accumulation panel<br>
<br><br>
Team wrenches - I feel like I've seen a provision in the Code for
installing a sub-panel to aggregate PV inverter outputs for the purpose
of simplifying the actual grid connection (such as for a line-side tap)
but I can't find it in 690. I also seem to remember specific
verbiage that needs to be on the panel along the lines of "PV
circuits only. Do not add load breakers." to ensure compliance
with 690.64(B). Does anyone know where I can find this info in the
NEC?<br><br>
<br>
Andrew Truitt<br>
Standard Solar Inc.<br><br>
<br>
-- <br>
"Don't get me wrong: I love nuclear energy! It's just that I prefer
fusion to fission. And it just so happens that there's an enormous fusion
reactor safely banked a few million miles from us. It delivers more than
we could ever use in just about 8 minutes. And it's
wireless!"<br><br>
~William McDonough<br>
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<font color="#0000FF">Drake Chamberlin<br>
Athens Electric<br>
OH License 44810<br>
CO License 3773<br>
NABCEP </font><font size=1 color="#0000FF">TM
</font><font color="#0000FF">Certified PV Installer <br>
Office - 740-448-7328<br>
Mobile - 740-856-9648 </font></body>
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