CSLB C-46 Solar ContractorPlanning and EstimatingHard
A C-46 contractor is performing a site analysis for a residential rooftop PV system. During the inspection, they identify several existing penetrations (e.g., plumbing vents, chimneys, skylights) that will significantly constrain the available unshaded roof space. The client insists on maximizing system size within the available area. Which design approach is most effective for this scenario?
- ARelocating all existing roof penetrations to create one large, clear area.
- BUtilizing multiple small arrays, each optimized for an unshaded roof section.
- CInstalling a ground-mounted system to avoid rooftop obstructions entirely.
- DDesigning a single, contiguous array over all available roof sections, regardless of penetrations.
Show answer & explanationAnswer & explanation
Correct answer: B. Utilizing multiple small arrays, each optimized for an unshaded roof section.
Utilizing multiple small arrays allows the contractor to maximize the use of fragmented, unshaded roof sections around penetrations, which is more effective than trying to force a single large array or undertaking costly relocation of penetrations. This approach is often facilitated by microinverters or optimizers.
Why the other options are wrong
- A. Relocating existing roof penetrations (plumbing, chimneys) is extremely costly, complex, and often impractical or prohibited, making it an unrealistic solution.
- C. While ground-mounting avoids rooftop obstructions, the question implies the client wants a rooftop system, and ground-mounting may not be feasible or desired for other reasons (e.g., available land, cost).
- D. Designing a single contiguous array over penetrations would lead to significant self-shading or require cutting modules, reducing efficiency and complicating installation.
Fragmented Roof PV Design
Designing PV systems for roofs with numerous obstructions by segmenting the array into multiple smaller, independently optimized sections.
- Maximizes module count on complex roofs.
- Often paired with module-level power electronics (MLPE).
- Requires careful layout to avoid self-shading.
Memory trick: Divide and conquer: small arrays fit where one big one can't.