When selecting array racking and mounting systems for pitched-roof applications, the optimal solution relies on many factors, including structural requirements, aesthetics, ease of installation, wire management and module grounding, roof clearances and compatibility with the desired module.

Mounting solutions and combinations provide varying clearances between the roof and the modules, which can impact aesthetics, cell temperatures and access beneath the array. Suitable roof attachment options vary based on the roofing material and the type of substructure under the array. Racking system features may include colors and finishes, preassembled components, universally sized module clamps, click-in-place hardware, telescoping rails, streamlined hardware sizes and types, and clampless and railless designs.

This article provides overviews of  pitched-roof attachment and racking product lines and identifies key features to consider. Several racking systems have been tested for use with integrated bonding and grounding hardware per UL 467, or UL 2703, which specifically addresses PV racking systems, module clamps, module frames, and grounding and bonding components.

Rail-Based Mounting Systems

About a decade ago, the introduction of rail-based mounting systems that employ top-down module fastening resulted in a significant reduction in installation time for pitched-roof arrays. The availability of these systems roughly coincided with module manufacturers’ shift to quick-connect module leads that simplify array wiring and facilitate the use of top-down racking systems. Today, rail-based racking systems are used in most pitched-roof applications, and manufacturers are introducing increasingly refined products.

 

Click the link below to read about the different types of pitched roof racking systems by manufacturer.

http://solarprofessional.com/articles/products-equipment/racking/module-racking-and-mounting-systems-for-pitched-roof