[RE-wrenches] Rail concerns (was: Top of POST mount)

[William Miller]

Friends:

When installing modules on extruded rail systems, I worry that any 
vibration or motion could loosen top-down clamps.  Unlike bottom-up systems 
that install with tried-and-true bolts and lock washers through captive 
holes, clamp systems seem less "positive" in holding capability.  If one 
rail in the proposed design moves in relation to the other, the clamps 
could loosen and the modules could eventually slide right off the rail.  It 
appears that wind turbulence could rock the modules in the proposed design, 
there is a lot of leverage for that.  This might loosen clamps.

I hesitate to design my own racking.  Small business management is all 
about controlling risk.  I do not want to be responsible for damaged 
modules if my design fails.

At least one local AHJ forbids home-brew racks for a permitted system.  I'm 
not sure I support that restrictive approach.  I might suggest allowing 
them for owner-builder systems where the home owner assumes the 
liability.  For myself, the remaining tasks associated with installing a 
system properly have enough pitfalls without me playing structural engineer.

And lastly, it is my understanding that Solar World had temporarily 
abandoned mounting holes in the back rails of their new "Plus" modules (my 
quotes) and even abandoned the flanges altogether.  According to what I 
heard, industry pressure forced them to add them back in, but as an 
option.  This is third-hand knowledge, but I do know that removing the 
option to mount panels with through bolts would be a big mistake.

William Miller




>Here is my "cobulated" idea, admittedly done this way to take advantage of 
>parts in stock:
>
><http://www.fafcosolar.com/download/402/Cobulate.pdf>http://www.fafcosolar.com/download/402/Cobulate.pdf
>
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