[RE-wrenches] Hurricane damage to solar arrays

Glenn Burt glenn.burt at glbcc.com
Fri Sep 15 07:07:09 PDT 2017


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 at 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 <jason at 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 <jamesrudolph99 at 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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