[RE-wrenches] Over-torquing Module Clamps?

[Ray]

I don't think impact drivers should be used at all, unless they have a 
way to adjust torque.  Instead, use a drill/ driver with torque setting 
set fairly low, and do a final tightening with a torque wrench.  Also, 
you need to be really careful what speed you use;  even with low torque, 
the screws can start binding from over heating, if driven too fast.

Ray Walters
Remote Solar
303 505-8760

On 9/4/21 12:08 PM, Jerry Shafer wrote:
> Wrenches
> its not the tool its the user so when I hear about impacts got to know 
> the feel.
> Jerry
>
> On Fri, Sep 3, 2021 at 12:06 AM Corey Shalanski <coresolar at gmail.com 
> <mailto:coresolar at gmail.com>> wrote:
>
>     Wrenches,
>
>     (This question actually does refer to the proper use of 'wrenches'...)
>
>     While inspecting some recent work from one of our contractors, we
>     noted that the PV module clamps had been torqued to ~150% of the
>     racking manufacturer's specified value. My question is whether
>     that might have any detrimental effect on the modules (frame,
>     glass, cells, seal, etc) and whether it would be worth loosening
>     the clamps and re-torquing them to the proper spec? For reference,
>     224 modules are installed.
>
>     We were made aware that the contractor used an impact driver on
>     the clamps, which accounts for the excessive torque applied. I
>     definitely understand the temptation to use an impact driver
>     for just about any hardware that needs turning—but my
>     understanding is also that impact drivers are generally
>     incompatible with machine screws. So my other question to the
>     group is whether anyone has had success in dissuading
>     subcontractors from using impact drivers so liberally on project
>     sites? Any advice is appreciated.
>
>     --
>     Corey Shalanski
>     Jah Light Solar
>     Portland, Jamaica
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