I wonder if a third rail would have prevented many of these escapees.Not even
attached to the structure, just to every module.
GlennSent from my 'smart' phone so please excuse spelling and typographical
errors.
------ Original message------From: RayDate: Fri, Sep 15, 2017 9:43 AMTo:
re-wrenches@lists.re-wrenches.org;Cc: Subject:Re: [RE-wrenches] Hurricane
damage to solar arrays
What was the pressure rating for the modules that got sucked off
the racks? Also, is it possible that flying debris caused some of
the random location module failures?
Ray Walters
Remote Solar
On 9/14/17 1:53 PM, Jason Szumlanski
wrote:
More early
anecdotal data...
We are finding
NO anchors pulled out of roofs, regardless of roof type or
attachment type. That is clearly not the failure point. We
also see no attachment to L-foot or L-foot to rail issues. And
contrary to my expectation, we see no t-bolt failures. What's
happening? The panels themselves are flexing (bowing)
sufficiently to work their way right out of the mid-clamps.
This applies both to Unirac's older 1-inch space clamps and
newer 1/4 inch bonding mid-clamps.
This attached
pictured system had panels on a north roof pitched very
slightly to the south. We had northeast hurricane winds in
this area, and the way the wind went under these panels was
obviously what caused the panels themselves to fail. This is
an essentially flat roof commercial application. It was bad
luck to have the wind direction from the northeast corner (the
NW edge of the eye wall passed right over this area). But we
are seeing similar results on residential pitched hip and
gable roofs in terms of the failure mode.
What's
interesting is that there is no rhyme or reason to where in
the array we see damage. I have seen absolutely no
catastrophic damage on a residential roof - just one or 2
modules mostly. And the missing module can be on the lower
edge, upper edge, or right in the middle of the array. More
often than not, the t-bolt and mid-clamp assembly is still
sitting right there in the channel of the Unirac Solarmount
rail, but a module is missing. It's quite freaky.
And much like
tornado damage I have seen on TV, houses adjacent to each
other have very different fates. We have a new community (100+
homes slated for solar) with about two dozen homes completed,
and just one home had a panel pop out in the middle of an
array. It was gently deposited onto the adjacent panel with
absolutely no damage and the DC leads still connected to the
microinverter.
One issue we
are facing is that when panels fly off, something has to give
with the DC leads to microinverters. No panel leads have been
broken so far. In most cases, the MC4 connectors simple
un-snap somehow - no loss of crimped connectors. We have a few
cases of leads ripped out of the microinverter case
completely. The microinverter bracket is badly bent on many
microinverters, indicating that there was tremendous force
until something gave up. I am extremely hesitant to reuse
these microinverters because the force on the DC input leads
must have been huge. I think we are going to insist on
microinverter replacement when replacing modules in these
cases.
Hopefully I
will have more, but not too much more to come. It looks like
we did very well here (as an industry). There are spotty
issues, but it's far from the catastrophe that kept me up for
multiple nights before and after Irma. Then again, many people
have not returned home yet.
Jason Szumlanski
Florida Solar Design Group
On Wed, Sep 13, 2017 at 6:18 PM,
Jason Szumlanski <ja...@floridasolardesigngroup.com>
wrote:
I'm
based in Fort Myers and we cover the hardest hit areas
from Irma. We are in the "stuff" right now, so I'll
make this brief until I have more time, which might be
a while. We are seeing quite a bit of minor damage and
some major damage. We're getting calls from all
dealers' customers and a couple of our own clients. We
have several homes with one or two panels dislodged.
There is no rhyme or reason. Some are middle of
arrays, some on edges. Panels are ripped right off
rails, leads ripped from microinverters. Strangely, it
looks like the panel j-box connection and MC4
connectors survived better than the microinverter end
of the DC leads. Amazingly, we have several panels
that were blown onto driveways, other roofs, and pool
cages with NO DAMAGE except frame scrapes. Very weird.
We haven't seen a shattered panel yet, but it's early.
I'm
heading to a self-storage facility tomorrow where
there are three 25kw systems on different buildings.
Two buildings are unscathed. One building lost ALL of
the panels apparently. Tornado? Hard to say.
So
far (other than the 25kw I have not evaluated) we have
not seen a single fastener pulled out. All of the
failures are panel top and mid clamps at this time.
Anchor and rails remain intact. Possibly installation
errors? Possibly sheared off T-bolts? Hard to tell and
we may never fully know.
We
generally require 48 inch spacing between anchors into
trusses for engineered systems. The pullout values are
pretty high. It looks like the attachment points into
the roof are not going to be the failure point in the
systems in Florida, but there is a LOT of work to be
done still. It's going to be a very interesting few
months ahead!
Jason
Szumlanski
Florida
Solar Design Group
On Tue, Sep 12, 2017 at 3:09
PM, James Rudolph <jamesrudolp...@gmail.com>
wrote:
Aloha Everyone,
I was just wondering how all the PV
arrays did during these storms?
Does Florida have higher pull out
values and wind designs for their PV/H20
systems?
Is there any thing the rest of us could
learn from all this?
Photos?
Mahalo Nui Loa,
James
B. Rudolph
Hawaii
Unified
Director
of Energy
ES
Electrician #
10816
NABCEP
Certified PV
Installer #
091209-155
80
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