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<p> Ground mounts do NOT require RSS. We hashed this out years ago
on the Wrenches list, when NEC 2017 came out.</p>
<p>See Figure 690.1(B) Note (2): <i>" The PV system disconnect in
these diagrams separates the PV system from all other systems".</i></p>
<p>Thus, the PV disconnect is defined as the transition point from
the PV system to all other systems, like battery or inverter
systems. The installer/ designer decides where to put that
disconnect. I usually put it on the wall before it goes into the
building, and I have never had an inspector question that. <br>
</p>
<p>Thanks,<br>
</p>
<pre class="moz-signature" cols="72">Ray Walters
Remote Solar
303 505-8760</pre>
<div class="moz-cite-prefix">On 2/1/22 10:06 AM, William Miller
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:625c5135422d4310be0382b6e3d8025f@mail.gmail.com">
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<div class="WordSection1">
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">Jay:</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">Here
is the text from 2017:</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">690.12
Rapid Shutdown of PV Systems on Buildings. PV</span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">system
circuits installed on or in buildings shall include a
rapid</span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">shutdown
function to reduce shock hazard for emergency</span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">responders
in accordance with 690.12(A) through (D).</span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">Exception:
Ground mounted PV system circuits that enter buildings, of</span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">which
the sole purpose is to house PV system equipment, shall
not be</span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">required
to comply with 690.12.</span></i></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">The
wording is interesting. The requirement is directed at \u201cPV
system circuits\u2026\u201d, not PV arrays. The passage does not
specify where the PV feeding those circuits is located, it
just addresses where the circuits are, specifically \u201cin or
on a building.\u201d</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">The
only circuits that are exempt are those feeding a building
that serves only one purpose, to house PV equipment. For
circuits that enter building with other uses\u2014homes, garages,
barns, workshops, etc.-- it would seem there is a
requirement to have rapid shutdown systems (RSS).</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">Reading
through the rest of the section, I don\u2019t see any language
that gets us out of the requirement to reduce voltages to
less than 80 volts within 30 seconds inside the array
boundary, as in module level shutdown, regardless of
roof-top or ground-mount. Although the 2020 code includes
some differing language, I don\u2019t see it as exempting ground
mount systems.</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">The
moral of the story is this: For ground-mounts: either
install RSS or put your equipment (inverters, charge
controllers, batteries, BOS) in a separate building housing
only that equipment.</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">I
don\u2019t necessarily like the requirement, but I think it
exists. Jay, or anyone, please, please tell me I am reading
this incorrectly. </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">By
the way, regarding battery circuits, here is a quote from a
post by Bill Brooks on March 16, 2016:</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">In
the 2017 NEC, we were very careful to carve out all
batteries and loads,</span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">that
were previously part of PV systems, and place them in
their own</span></i></p>
<p class="MsoNormal"><i><span
style="font-family:"Verdana","sans-serif";color:#993366">articles.</span></i></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">I
have not read through the battery sections of the code to
verify this, I am taking Bill at his word.</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366">William
Miller</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<div>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#993366">Miller
Solar</span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#993366">17395
Oak Road, Atascadero, CA 93422</span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#993366">805-438-5600</span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#993366"><a
href="http://www.millersolar.com/"
moz-do-not-send="true"><span style="color:blue">www.millersolar.com</span></a></span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#993366">CA
Lic. 773985</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#993366"> </span></p>
</div>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#993366"> </span></p>
<div>
<div style="border:none;border-top:solid #b5c4df
1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
Jay [mailto:<a href="mailto:jay.peltz@gmail.com"
moz-do-not-send="true" class="moz-txt-link-freetext">jay.peltz@gmail.com</a>]
<br>
<b>Sent:</b> Tuesday, February 1, 2022 6:07 AM<br>
<b>To:</b> <a href="mailto:william@millersolar.com"
moz-do-not-send="true" class="moz-txt-link-freetext">william@millersolar.com</a>;
RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] Rapid Shutdown for
Off-grid systems</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal">2017 code has a specific
exception/clarification for ground mount solar that it does
not need RS. </p>
</div>
<div>
<p class="MsoNormal">It\u2019s in the first line after 690.12</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Jay</p>
</div>
<div>
<p class="MsoNormal"><br>
<br>
</p>
<p class="MsoNormal" style="margin-bottom:12.0pt">On Feb 1,
2022, at 12:13 AM, William Miller <<a
href="mailto:william@millersolar.com"
moz-do-not-send="true" class="moz-txt-link-freetext">william@millersolar.com</a>>
wrote:</p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<div>
<p class="MsoNormal"><span
style="font-family:"Tahoma","sans-serif"">\ufeff</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#1f497d">Jerry:</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#1f497d">Yes
it is required. Rapid Shutdown: NEC 690.12. All
buildings except dedicated solar buildings. Read it and
weep.</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#1f497d">William</span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#1f497d">Miller
Solar</span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#1f497d">17395
Oak Road, Atascadero, CA 93422</span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#1f497d">805-438-5600</span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#1f497d"><a
href="http://www.millersolar.com/"
moz-do-not-send="true">www.millersolar.com</a></span></p>
<p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#1f497d">CA
Lic. 773985</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p>
<p class="MsoNormal"><span
style="font-family:"Verdana","sans-serif";color:#1f497d"> </span></p>
<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
Jerry Shafer [mailto:<a
href="mailto:jerrysgarage01@gmail.com"
moz-do-not-send="true" class="moz-txt-link-freetext">jerrysgarage01@gmail.com</a>]
<br>
<b>Sent:</b> Monday, January 31, 2022 7:21 PM<br>
<b>To:</b> William Miller; RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] Rapid Shutdown for
Off-grid systems</span></p>
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal">William</p>
<div>
<p class="MsoNormal">Are you sure RSD is required on a
non habitable building, historically its not required.
Now that being said we use fire raptor with the best
results, yes it takes an extra conduite and might
require a button and power supply depending on
inverter application.</p>
</div>
<div>
<p class="MsoNormal">Jerry</p>
</div>
</div>
<p class="MsoNormal"> </p>
<div>
<div>
<p class="MsoNormal">On Mon, Jan 31, 2022, 9:57 AM
William Miller <<a
href="mailto:william@millersolar.com"
moz-do-not-send="true" class="moz-txt-link-freetext">william@millersolar.com</a>>
wrote:</p>
</div>
<blockquote style="border:none;border-left:solid #cccccc
1.0pt;padding:0in 0in 0in
6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt">
<div>
<div>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif"">Friends:</span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif"">It is
quite rare for us to install off-grid systems on
roof-tops. We have one coming up with about
20kW on a large barn roof. This will be our
first off-grid with a module-level rapid
shutdown requirement. I see no exemptions from
RSS for off-grid systems in the code. I have
looked at the options and this is what I have
found:</span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif""> </span></p>
<p class="m8583279663636586131msolistparagraph"><span
style="font-family:"Verdana","sans-serif"">1.</span><span
style="font-size:7.0pt"> </span><span
style="font-family:"Verdana","sans-serif"">Fire
Raptor</span></p>
<p class="m8583279663636586131msolistparagraph"><span
style="font-family:"Verdana","sans-serif"">2.</span><span
style="font-size:7.0pt"> </span><span
style="font-family:"Verdana","sans-serif"">Tigo
TS4-F</span></p>
<p class="m8583279663636586131msolistparagraph"><span
style="font-family:"Verdana","sans-serif"">3.</span><span
style="font-size:7.0pt"> </span><span
style="font-family:"Verdana","sans-serif"">AC
coupling with micro-inverters or optimizers</span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif"">No one of
these approaches seems ideal. The fire raptor
requires extra wiring for control leads. The
Tigo requires a wireless control system which
worries me about reliability. With AC Coupling
systems floating the proposed AGM batteries may
be awkward. Furthermore, with AC coupled
systems one cannot charge batteries unless the
mini-grid is operational, a big problem.</span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif"">Have any
of you implemented module-level RSS on a
battery-based inverter system? I looked in the
archives and found no threads that apply. Thank
in advance.</span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif""> </span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif"">William
Miller</span></p>
<p class="MsoNormal"
style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span
style="font-family:"Verdana","sans-serif""> </span></p>
<br>
</div>
</div>
<br>
</blockquote>
</div>
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