[RE-wrenches] Hurricane damage to solar arrays

Fri Sep 15 15:37:05 PDT 2017

Jason,
Thanks for the preliminary failure analysis of the latest hurricane
damage. Do you have any photos which shows the bent mounting plates
for the micros? Wouldn't that be an indication of the force applied
before something gave up? Good call to get new micros when the leads
and their attachments may have been compromised.
TIA,
Bill Loesch
Saint Louis, MO

	-----------------------------------------From: "Jason Szumlanski" 
To: "RE-wrenches"
Cc: 
Sent: 14-Sep-2017 20:26:09 +0000
Subject: Re: [RE-wrenches] Hurricane damage to solar arrays

    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  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  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               

Links:
------
[1] mailto:jason at floridasolardesigngroup.com
[2] mailto:jamesrudolph99 at gmail.com

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