PV Installation Test Prep practice questions and answers 2026. Tap an option to test yourself — you'll see the correct answer and a plain-English explanation for every question. Free, no login.
Q21What is the most likely cause if a grid-tied PV system's production suddenly drops to zero while the sun is shining?
✓ Correct answer: D. Loss of utility power causing inverter anti-islanding shutdown
A complete loss of production during sunny conditions in a grid-tied system typically indicates utility power loss. Most grid-tied inverters are required to shut down during utility outages for safety reasons (anti-islanding protection).
Q22When conducting annual maintenance on a roof-mounted PV array, what should be the first safety procedure implemented?
✓ Correct answer: C. Implementing proper lockout/tagout procedures
Before any maintenance work begins, the system should be de-energized following lockout/tagout procedures to ensure worker safety, which is a critical OSHA requirement for electrical work.
Q23Which monitoring data trend would most strongly indicate a need for module cleaning?
✓ Correct answer: B. Gradual decline in output over time with recovery after rainfall
A gradual decline in system output over time with immediate recovery after rainfall is a classic indication of soiling (dirt accumulation) on modules, which can be remedied by cleaning.
Q24In a commercial PV system with string inverters, what is the appropriate first step when troubleshooting one underperforming inverter?
✓ Correct answer: A. Check monitoring data and error codes for that specific inverter
Before making any physical changes or repairs, checking monitoring data and error codes is the most efficient first step to diagnose the specific issue with the underperforming inverter.
Q25According to NFPA 70E, what personal protective equipment (PPE) is typically required when taking voltage measurements on an energized 480V AC combiner box?
✓ Correct answer: D. Arc-rated clothing, insulated gloves with leather protectors, face shield with hard hat
Working on energized 480V equipment requires appropriate PPE including arc-rated clothing, insulated gloves with leather protectors, and face shield with hard hat to protect against potential arc flash hazards.
Q26Which of these measurements would most effectively verify proper operation of a maximum power point tracking (MPPT) function in an inverter?
✓ Correct answer: C. Comparing actual power output to theoretical maximum based on irradiance and temperature
Comparing actual power output to theoretical maximum based on irradiance and temperature is the most effective way to verify MPPT functionality, as it shows whether the inverter is optimizing power extraction from the array.
Q27A residential PV system shows 15% lower production than expected during winter months. What is the most likely cause?
✓ Correct answer: B. Snow accumulation on modules
Snow accumulation is the most likely cause of reduced production in winter months, as it physically blocks sunlight from reaching the modules, unlike the other options which would affect performance year-round.
Q28When documenting corrective maintenance, which of the following must be included according to best practices?
✓ Correct answer: A. Date/time of service, description of issue, corrective actions taken, and components replaced
Proper documentation requires all key elements: date/time of service, description of issue found, actions taken to resolve it, and components replaced (if any). This comprehensive documentation ensures proper record-keeping for warranty and future maintenance.
Q29What is the appropriate action when discovering several modules with visible backsheet cracks during an annual inspection?
✓ Correct answer: D. Document with photographs, record affected module serial numbers, and report to system owner
Backsheet cracks can lead to moisture ingress and safety hazards. Documenting with photographs, recording module serial numbers, and reporting to the system owner allows for proper warranty claims and replacement planning.
Q30Which seasonal factor most significantly affects PV module cleaning frequency in agricultural areas?
✓ Correct answer: C. Harvest season dust accumulation
In agricultural areas, harvest seasons often create significant dust that accumulates on modules, requiring more frequent cleaning to maintain optimal performance. Other options don't typically follow seasonal patterns that correlate with agricultural activities.
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