NABCEP Site Assessment 2 — Questions and Answers
Question 1: When evaluating a rooftop for solar installation, what is the primary concern regarding roof age?
- Color of the roofing material
- Remaining useful life relative to the system's lifespan (Correct answer)
- Slope of the roof surface
- Presence of skylights
Correct answer: Remaining useful life relative to the system's lifespan
A roof with insufficient remaining life may require costly removal and reinstallation of solar panels before its replacement, so remaining useful life should match or exceed the system's 25+ year lifespan.
Question 2: What instrument is used to measure the angle of a roof slope during a site assessment?
- Pyranometer
- Inclinometer (Correct answer)
- Anemometer
- Solarimeter
Correct answer: Inclinometer
An inclinometer (or digital level) measures the pitch or angle of the roof surface relative to horizontal.
Question 3: A site assessment reveals that a proposed array location receives significant shading from 9 AM to 11 AM in December. What is the MOST appropriate next step?
- Proceed with installation and accept the energy loss
- Use a solar pathfinder or software to quantify annual shading losses (Correct answer)
- Install only microinverters and ignore shading impact
- Reject the site without further analysis
Correct answer: Use a solar pathfinder or software to quantify annual shading losses
Quantifying shading losses with a solar pathfinder or simulation software allows an informed decision about system viability and appropriate mitigation strategies.
Question 4: Which of the following best describes magnetic declination and why it matters in site assessment?
- The difference between true north and magnetic north, affecting accurate compass-based azimuth readings (Correct answer)
- The tilt angle of the earth's axis relative to the sun
- The seasonal variation in solar noon time
- The degree of solar irradiance reduction due to atmosphere
Correct answer: The difference between true north and magnetic north, affecting accurate compass-based azimuth readings
Magnetic declination is the angular difference between true north and magnetic north, and must be corrected for when using a compass to determine array azimuth.
Question 5: What does a high albedo surface near a solar array indicate?
- Increased shading risk
- Increased reflected irradiance that can boost bifacial panel output (Correct answer)
- Higher wind loads on the array
- Reduced module operating temperature
Correct answer: Increased reflected irradiance that can boost bifacial panel output
High albedo surfaces reflect more sunlight, which can increase the irradiance reaching bifacial modules and boost their energy production.
Question 6: During a site assessment, you discover the service entrance equipment is rated at 200A with a main breaker of 200A. The utility allows a 120% rule. What is the maximum allowable solar backfed breaker size?
- 40A (Correct answer)
- 80A
- 160A
- 200A
Correct answer: 40A
Under the 120% rule, maximum OCPD = (200A × 120%) − 200A = 240A − 200A = 40A.
Question 7: What is the significance of identifying the utility interconnection point during site assessment?
- It determines the optimal tilt angle for the array
- It establishes where the solar system will connect to the grid and informs equipment and permitting requirements (Correct answer)
- It is used to calculate wind uplift loads
- It determines the appropriate module efficiency to specify
Correct answer: It establishes where the solar system will connect to the grid and informs equipment and permitting requirements
The interconnection point defines the technical requirements for grid-tied connection, including metering, disconnect, and utility approval processes.
NABCEP Site Assessment 2
When evaluating a rooftop for solar installation, what is the primary concern regarding roof age?