<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p>Is it possible there may have been loose mounting hardware here
and there? I've found quite a few loose clamps over the years on
many different systems from myself and reputable dealers. I've
found that using a impact driver really causes trouble; I now hand
tighten everything. Many of the threaded aluminum type blocks can
seize up when tightened at speed with a driver, and no lube. They
seem tight, could pass a torque wrench test, but actually are
seized up.</p>
<p>We've recently had a pole mount that ripped modules right off
their still tight mounting bolts, which I could only explain by a
mini tornado. This could be the explanation in your random
failures too. Another possibility are a vortex or turbulence
created by the nearby trees or the structure itself in very high
winds. We like to model wind loading as a simple vector force,
when we all know the reality is extremely dynamic.<br>
</p>
<p>Ray Walters</p>
<p>Remote Solar<br>
</p>
<br>
<div class="moz-cite-prefix">On 9/16/17 8:15 AM, Jason Szumlanski
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAE438R-RdCfwRhjS9+X_NeLjYMa14eO+3T58JBvTRF_UPm=3PQ@mail.gmail.com">
<div dir="ltr"><img class="mailtrack-img" alt=""
style="display:flex"
src="https://mailtrack.io/trace/mail/cdaca382690937054c13641404ea208655c68677.png?u=1613865"
moz-do-not-send="true" width="0" height="0">
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">I generally
agree on all points. I'd love to use three rails on all
systems, but there is an economic factor, and as Tom mentions,
a third rail doesn't necessarily stop glass being sucked out
or a tree landing on the array. At what point do we cease
over-engineering the mounting structure and the module itself?
I can see hardening backup systems and critical infrastructure
(utility scale solar included), but residential grid-tie
systems should be built with an acceptable loss criteria. I
know I might take some heat for that statement, but given the
anecdotal evidence of the small percentage of issues relative
to the installed base we have, I think it's the right answer.</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">Also, one thing
we are seeing (small sample size) is modules being plucked
from random parts of the array, not necessarily on the lower
or side edges. Very odd. </div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif">Jason</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_default"
style="font-family:arial,helvetica,sans-serif"><br>
</div>
<div class="gmail_extra">
<br>
<div class="gmail_quote">On Fri, Sep 15, 2017 at 3:52 PM, Tom
Lane <span dir="ltr"><<a href="mailto:tom@ecs-solar.com"
target="_blank" moz-do-not-send="true">tom@ecs-solar.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="auto">Hurricanes wind create both suction up
lift and direct pressure against the glass frame wall of
the module -- if a module is to be held securely it must
be attached 1/3 or 1/4 of the way from top to bottom by
each of the two rails . If modules are facing due South
and the wind force comes from the east or west the force
will start pealing off one module at at time . For
example if the winds shearing force is from the west the
first module on that end should have an extra rail in
the middle with two extra clamps BECAUSE when that first
one goes it will start peeling off each one one at a
time until that wind band passes . It is critical on
raise systems on flat roofs that the two end modules use
the struts with two ( 11/2 sets of mounting hardware per
module) and the first three or at least first two
modules be X braced with aluminum L bars bolted with 3/8
bolts across the back struts in front of and back of the
struts with the L bars to prevent peeling down the row
or bank of modules the same as modules mounted flat on a
roof . Enough suction force from high wind speeds can
suck the glass right out of the frame wall - using three
rails per module , two each 1/4 of the way from the top
and bottom and one directly in the middle can help . I
also suggest using only 60 cell modules in wind zones
over 150 MPH with two rails minimum maybe even three on
high rises .The frame walls on 72 cell modules is trying
to hold too much glass in place for just two rails . On
ground mounts that are adjustable lower the array to 15%
or less and on smaller home owner ground arrays attach
motorcycle tie down straps on the end corners and middle
hooked to extra D rings attached to the array (
especially to the corners of Top of Pole Racks ) to
mobile home screw in ground anchors AND if possible
strap plywood over the glass front . GatorTom PS :
having insurance is a good investment when a monster
100' Live Oak tree topples forward onto your array . Or
a car or boat gets blown onto your roof .</div>
<br>
______________________________<wbr>_________________<br>
List sponsored by Redwood Alliance<br>
<br>
List Address: <a
href="mailto:RE-wrenches@lists.re-wrenches.org"
moz-do-not-send="true">RE-wrenches@lists.re-wrenches.<wbr>org</a><br>
<br>
Change listserver email address & settings:<br>
<a
href="https://mailtrack.io/trace/link/fb4243e47dfd1f174f7212354d586f680787c342?url=http%3A%2F%2Flists.re-wrenches.org%2Foptions.cgi%2Fre-wrenches-re-wrenches.org&userId=1613865&signature=719c762d6e89b309"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://lists.re-wrenches.org/<wbr>options.cgi/re-wrenches-re-<wbr>wrenches.org</a><br>
<br>
List-Archive: <a
href="https://mailtrack.io/trace/link/8566ffd470b9fc56c4306a3fddc3a6b560dad976?url=http%3A%2F%2Fwww.mail-archive.com%2Fre-wrenches%40lists.re-wrenches.org%2Fmaillist.html&userId=1613865&signature=36607c931a1b194e"
rel="noreferrer" target="_blank" moz-do-not-send="true">http://www.mail-archive.com/<wbr>re-wrenches@lists.re-wrenches.<wbr>org/maillist.html</a><br>
<br>
List rules & etiquette:<br>
<a
href="https://mailtrack.io/trace/link/78a29b69dfb3a3b5703c9b0b374f54daf63e2f36?url=http%3A%2F%2Fwww.re-wrenches.org%2Fetiquette.htm&userId=1613865&signature=1f4692aab54e1f85"
rel="noreferrer" target="_blank" moz-do-not-send="true">www.re-wrenches.org/etiquette.<wbr>htm</a><br>
<br>
Check out or update participant bios:<br>
<a
href="https://mailtrack.io/trace/link/4a9d88cd856450b2e68b6d0add4c478828c77931?url=http%3A%2F%2Fwww.members.re-wrenches.org&userId=1613865&signature=ab95a6460b96c794"
rel="noreferrer" target="_blank" moz-do-not-send="true">www.members.re-wrenches.org</a><br>
<br>
<br>
</blockquote>
</div>
<br>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
List sponsored by Redwood Alliance
List Address: <a class="moz-txt-link-abbreviated" href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a>
Change listserver email address & settings:
<a class="moz-txt-link-freetext" href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a>
List-Archive: <a class="moz-txt-link-freetext" href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html">http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html</a>
List rules & etiquette:
<a class="moz-txt-link-abbreviated" href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a>
Check out or update participant bios:
<a class="moz-txt-link-abbreviated" href="http://www.members.re-wrenches.org">www.members.re-wrenches.org</a>
</pre>
</blockquote>
<br>
</body>
</html>