NABCEP Site Assessment 3 — Questions and Answers
Question 1: Which document is typically required from the utility before beginning a grid-tied solar installation?
- Certificate of occupancy
- Interconnection agreement or permission to operate (Correct answer)
- Environmental impact statement
- UL listing for all components
Correct answer: Interconnection agreement or permission to operate
An interconnection agreement or permission to operate (PTO) from the utility authorizes the customer-sited system to connect to and operate in parallel with the grid.
Question 2: A site assessment for a ground-mount system should include soil testing primarily to evaluate what factor?
- Soil conductivity for grounding electrode design
- Bearing capacity and suitability for pile-driven foundations (Correct answer)
- Soil pH for corrosion resistance of aluminum racking
- Organic content to assess vegetation shading risk
Correct answer: Bearing capacity and suitability for pile-driven foundations
Soil bearing capacity determines whether driven piles, helical piers, or concrete ballast foundations are appropriate to safely support the array structure.
Question 3: When assessing a flat commercial roof for a ballasted solar array, which factor is MOST critical to evaluate first?
- Roof membrane color
- Structural dead load capacity (Correct answer)
- Presence of rooftop HVAC units
- Age of the building
Correct answer: Structural dead load capacity
Ballasted systems add significant weight; the roof structure must be verified to support both the existing dead loads and the additional solar array loading.
Question 4: What is the purpose of performing a shading analysis using the Solar Pathfinder at multiple points across a proposed array area?
- To determine the optimal inverter string configuration
- To identify spatially varying shading that could create mismatched string performance (Correct answer)
- To measure the exact solar irradiance at the site
- To calculate the magnetic declination for the location
Correct answer: To identify spatially varying shading that could create mismatched string performance
Shading can vary across an array footprint, and identifying these differences is essential for optimizing string layout and mitigation strategies like optimizers.
Question 5: A site assessor notes that the proposed installation location is within an HOA-governed community. What is the primary action to take?
- Proceed without notification since federal law overrides HOA restrictions
- Review HOA covenants and local solar access laws to determine applicable aesthetic or placement requirements (Correct answer)
- Reduce system size to minimize visual impact
- Install the system only on non-street-facing roof surfaces without approval
Correct answer: Review HOA covenants and local solar access laws to determine applicable aesthetic or placement requirements
Many states have solar access laws that limit HOA authority to prohibit solar, but HOAs may still impose reasonable aesthetic requirements, so reviewing both is essential.
Question 6: What does a Net Energy Metering (NEM) tariff allow a solar customer to do?
- Export excess electricity to the grid and receive a bill credit (Correct answer)
- Sell electricity at the wholesale market rate
- Store excess solar energy in a utility-owned battery
- Eliminate all utility charges
Correct answer: Export excess electricity to the grid and receive a bill credit
NEM allows customers to export excess solar generation to the grid and receive a credit on their utility bill, typically at the retail electricity rate.
Question 7: Which of the following conditions would MOST likely require a structural engineer's review before a rooftop solar installation?
- A new composition shingle roof installed 2 years ago
- A roof with visible sagging, deteriorated rafters, or questionable structural integrity (Correct answer)
- A south-facing roof with 30-degree pitch
- A roof with existing vent pipes that require flashing
Correct answer: A roof with visible sagging, deteriorated rafters, or questionable structural integrity
Signs of structural compromise such as sagging or deteriorated framing indicate potential load-carrying deficiencies that require a licensed structural engineer to evaluate before adding solar loads.
NABCEP Site Assessment 3
Which document is typically required from the utility before beginning a grid-tied solar installation?