<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif">Dave,</div><div class="gmail_default" style="font-family:verdana,sans-serif"><br></div><div class="gmail_default" style="font-family:verdana,sans-serif">
I looked at the BR24L70RP a while back. It's really a 2-space, 4 cuircuit panel. I think my conclusion was you actually need a single quadplex breaker with common trip center and outer breakers to get (2) 2-pole breaker functionality. The quadplex breakers come in a variety of mixed rating (i.e. 15A center and 20A outer breakers). They are not readily stocked and not cheap. We stuck with Sq D QO load centers for that reason.</div>
<div class="gmail_default" style="font-family:verdana,sans-serif"><br></div><div class="gmail_default" style="font-family:verdana,sans-serif">Am I missing something?</div><br><br><div id="WISESTAMP_SIG_gmail_session" href="http://WISESTAMP_SIG_gmail_session">
<div style="font-size:13px;font-family:Verdana,Arial,Helvetica,sans-serif"><div style="margin:0 0 8px 0"><p style="margin:0"><span><span>Jason Szumlanski </span></span></p><p style="margin:0"></p><div class="gmail_default" style="font-family:verdana,sans-serif;display:inline">
Fafco Solar</div><br> <p></p><div style="clear:both"></div></div><img src="https://wisestamp.appspot.com/pixview.gif?p=chrome&v=3.42.0&t=1403887061513&u=dedcb4cd140ce271" width="1" height="1"></div><img src="http://ws-stats.appspot.com/ga/pixel.png?yes__count=true &e=legacy_impression"></div>
</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Jun 27, 2014 at 11:32 AM, Dave Click <span dir="ltr"><<a href="mailto:daveclick@fsec.ucf.edu" target="_blank">daveclick@fsec.ucf.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">This is an interesting conversation, but I'm not sure it's going to really impact anything.<br>
<br>
When an inverter is listed, it is tested with some "maximum output overcurrent protection" as part of its rating per UL 1741. Typically inverter manufacturers set this to be just above the inverter's max current + 25%. As you know, many inverters can work at more than one voltage, so for the SB5s their max current ratings at 277/240/208V are 18/20.8/24A, respectively. The max overcurrent protection is 50A. This figure often appears in the manual but not in the data sheet. For SMA, it's in the manuals. For some manufacturers, it's only available from tech support.<br>
<br>
For the Sunny Boy line, the only way you could have more than one inverter on a shared OCPD is if you have two SB5s operating at 277V (18.1A rated current each, so 2x18.1x1.25 < 50A). The SB6, SB7, and SB8 all have currents too high to make this work, as they share the 50A max OCPD. The SB3/3.8/4 have a max OCPD of 30A, which is too low to double-up since each SB3 requires an OCPD of at least 20A. The TLs don't work either, as the max for any unit is too low. I don't see it in the SMA manual, but I know that in other manuals I've seen a manufacturer requirement for a dedicated OCPD. The only inverters I know of that have a max OCPD rating far beyond their rated current are micro-inverters.<br>
<br>
As for the shared disconnect, since at least the 2005, 690.15 has noted, "A single disconnecting means in accordance with 690.17 shall be permitted for the combined ac output of one or more inverters or ac modules in an interactive system." That being said, the NEC requires ac modules and micro-inverters to have ac disconnects (connectors, typically) per 690.6 and 690.15(A). 690.15 notes that an inverter be able to be disconnected from all sources, but if doubling up these SB5s you could argue that this shared disconnect accomplishes that via the anti-islanding protection... so I agree now that this is a grey area.<br>
<br>
Anyway, it comes down to whether it's worth worrying about this for what is an extremely small subset of compatible inverter configurations, when you can just do something like install a $50 Eaton BR24L70RP (70A bus, 240V, 4 spaces) with two 30A breakers and be on your way.<br>
<br>
DKC<div class="HOEnZb"><div class="h5"><br>
<br>
<br>
<br>
<br>
On 2014/6/27, 6:53, Richard L Ratico wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
I may be playing devil's advocate here, but I want to add a few thoughts. Jay, I<br>
just looked at Fronius and SMA inverter data sheets. I found no spec. for an<br>
output OCPD, only a spec for max. output current.<br>
William, most inverters now come with integrated DC/AC discos. Dave, 2014 NEC<br>
705.12(D)(1), IMHO, specifies ONE OCPD for the entire interconnected power<br>
system, not individual OCPD for each inverter.<br>
<br>
Generally speaking OCPD is provided for the circuit conductors in a system, not<br>
the individual pieces of equipment. If the equipment manu. specifies OCPD, that<br>
is a different story.<br>
<br>
I understand the 2014 code to require appropiate OCPD for all the conductors<br>
from the panelboard to the inverter. If that can be accomlished with one device<br>
at the panel, it meets code. That said, code is a MINIMUM standard.<br>
<br>
Bottom line, I agree with Corey that there is no code requirement for individual<br>
OCPD for each inverter. If there is, unfortunately, it is insufficiently<br>
explicit such that we are having this conversation.<br>
<br>
Dick Ratico<br>
Solarwind Electric<br>
<br>
<br>
--- You wrote:<br>
I have never seen an inverter that does not specify a OCPD size.<br>
<br>
Jay<br>
Peltz power.<br>
<br>
Sent from my iPhone<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Jun 26, 2014, at 3:20 PM, Dave Click <<a href="mailto:daveclick@fsec.ucf.edu" target="_blank">daveclick@fsec.ucf.edu</a>> wrote:<br>
<br>
Corey,<br>
<br>
The line of reasoning is faulty. It's 705.12(D)(1). Micro-inverters are the<br>
</blockquote>
exception because they are specially listed to share a breaker. As for the other<br>
inverters, doubling them up on a single breaker / disconnect probably goes<br>
against their installation instructions [110.3(B)] and it's unlikely that you<br>
could put multiple units on a single breaker anyway because when you take (2<br>
inverters) x (rated current) x (1.25) you will probably come up with a minimum<br>
breaker size that is larger than the maximum allowed under the NRTL listing to<br>
UL 1741.<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Dave<br>
<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On 2014/6/26, 16:18, Corey Shalanski wrote:<br>
We considered the necessity to shut down individual inverters and determined<br>
</blockquote></blockquote>
that the added costs of an inverter output combiner panel were not merited. I<br>
agree that in theory it seems beneficial to be able to switch each inverter<br>
individually, but how often does this occur in practice? For the relatively<br>
infrequent cases where we need to return to a jobsite and shut down an inverter<br>
- for troubleshooting/removal/etc. - we do not mind shutting down the other<br>
inverters (up to a limit) for what is hopefully a short period of time.<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Again, this whole line of reasoning may be shown to be faulty if someone can<br>
</blockquote></blockquote>
directly point to the Code section that requires OCPD on each individual<br>
inverter.<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
--<br>
Corey<br>
$E1eB<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
On Thu, Jun 26, 2014 at 9:20 AM, <<a href="mailto:re-wrenches-request@lists.re-wrenches.org" target="_blank">re-wrenches-request@lists.re-<u></u>wrenches.org</a>><br>
</blockquote></blockquote></blockquote>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Message: 5<br>
Date: Wed, 25 Jun 2014 19:17:57 -0700<br>
From: William Miller <<a href="mailto:william@millersolar.com" target="_blank">william@millersolar.com</a>><br>
To: RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-<u></u>wrenches.org</a>><br>
Subject: Re: [RE-wrenches] Combining Multiple Inverters<br>
Message-ID: <<a href="mailto:04F4B8FD-E280-4BF2-B5A4-C2FCA8D1C7A6@millersolar.com" target="_blank">04F4B8FD-E280-4BF2-B5A4-<u></u>C2FCA8D1C7A6@millersolar.com</a>><br>
Content-Type: text/plain; charset="utf-8"<br>
<br>
Not allowed. You need a dedicated OCPD. Plus seems like a really bad idea.<br>
</blockquote></blockquote></blockquote>
How do you shut down just one inverter?<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<br>
<br>
Miller Solar<br>
</blockquote></blockquote></blockquote>
--- end of quote ---<br>
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