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

[Jason Szumlanski]

I tend to agree about the clamps, and in a case like this where there is
little risk of an expensive mistake with a voided warranty, I would
actually drill holes in the frame and use bottom clamps in addition to
top clamping.

 

Jason Szumlanski

Fafco Solar

 

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of William
Miller
Sent: Tuesday, March 22, 2011 5:48 PM
To: RE-wrenches
Subject: [RE-wrenches] Rail concerns (was: Top of POST mount)

 

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
 

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