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Question 1. Which NEC article specifically governs the installation of photovoltaic (PV) systems? A) Article 300 B) Article 690 C) Article 210 D) Article 500 Answer: B Explanation: NEC Article 690 contains the requirements for the safe installation of solar photovoltaic systems, including wiring, grounding, and over‑current protection. Question 2. In a grid‑tied PV system, what is the primary function of a rapid‑shutdown device? A) To disconnect the inverter from the utility grid B) To reduce the voltage of all conductors within a specified distance of the array to a safe level when activated C) To limit the maximum power point of the modules D) To provide surge protection for the AC side Answer: B Explanation: Rapid‑shutdown devices must reduce the voltage on conductors within 10 ft of the array to ≤ 30 V (or 80 V for some modules) to protect firefighters and first responders.
Question 3. When sizing a PV string, which two electrical parameters are most critical to calculate? A) Open‑circuit voltage (Voc) and short‑circuit current (Isc) B) Maximum power voltage (Vmp) and maximum power current (Imp) C) Temperature coefficient and module efficiency D) Series resistance and shunt resistance Answer: B Explanation: Vmp and Imp define the operating point of the string under maximum power conditions and are used to select conductors, over‑current devices, and inverter input ratings. Question 4. A solar thermal collector is rated at 60 % thermal efficiency. If the solar irradiance on a clear day is 800 W/m², what is the useful heat gain per square meter? A) 480 W B) 600 W C) 800 W D) 1200 W Answer: A Explanation: Useful heat = efficiency × irradiance = 0.60 × 800 W/m² = 480 W/m². Question 5. Which of the following is NOT a typical component of a closed‑loop solar domestic hot‑water system?
C) To house the solar modules D) To store excess energy in batteries Answer: B Explanation: A combiner box aggregates the positive (or negative) conductors from several strings, includes fuses or breakers, and routes the combined current to the inverter. Question 8. Which grounding method is required for the metal frame of a photovoltaic module according to NEC 690.45? A) No grounding is required for non‑metallic frames B) Ground the frame to the system grounding electrode conductor (GEC) only if the frame is conductive C) Ground each module individually to the building grounding system D) Use a separate isolated grounding system for each array Answer: B Explanation: Conductive metal frames must be bonded to the system grounding electrode conductor to ensure equipotential bonding and lightning protection. Question 9. A micro‑inverter is installed on each module. Which advantage does this configuration provide over a central string inverter? A) Lower overall system cost B) Simplified AC wiring only C) Improved energy harvest under shade and module mismatch conditions
D) Elimination of the need for a grounding conductor Answer: C Explanation: Micro‑inverters perform MPPT at the module level, reducing the impact of shading or mismatched modules on overall system performance. Question 10. What is the typical temperature coefficient of power for crystalline‑silicon PV modules? A) +0.05 %/°C B) – 0.05 %/°C C) – 0.30 %/°C D) – 0.45 %/°C Answer: C Explanation: Crystalline‑silicon modules usually have a power temperature coefficient around – 0.30 % per degree Celsius, meaning power decreases as temperature rises. Question 11. In a solar pool heating system, which component prevents water from draining back into the collector when the pump is off? A) Check valve B) Pressure relief valve C) Air vent D) Thermostat Answer: A
Question 14. Which of the following best describes an “evacuated‑tube” solar collector? A) A flat‑plate absorber with air space B) A glass tube with a vacuum surrounding the absorber to reduce heat loss C) A series of metal fins exposed to the sun D) A solar‑powered heat pump Answer: B Explanation: Evacuated‑tube collectors consist of glass tubes that are evacuated to create a vacuum, dramatically reducing convective heat loss and improving efficiency. Question 15. In a battery‑backed off‑grid PV system, what is the purpose of a charge controller? A) To convert DC to AC power B) To regulate the voltage and current entering the battery, preventing over‑charge and deep discharge C) To provide rapid shutdown of the array D) To monitor solar irradiance Answer: B Explanation: The charge controller ensures the battery is charged safely, maintaining appropriate voltage levels and preventing over‑charging or excessive discharge.
Question 16. Which NEC requirement applies to the labeling of a PV system disconnecting means? A) Must be labeled “Main Service Disconnect” B) Must include the system voltage, maximum DC current, and “PV Disconnect” designation C) No labeling is required if the disconnect is inside a locked panel D) Only the AC side must be labeled Answer: B Explanation: NEC 690.14 requires the disconnect to be clearly labeled with system voltage, maximum DC current, and identification as a PV disconnect. Question 17. During a roof‑mount solar installation on a tile roof, which flashing method is most commonly used to maintain the roof’s weather integrity? A) Sealant only B) Pitched‑roof flashing with metal base flash and tile over‑lap C) Screw‑down mounting without flashing D) Use of a rubber membrane under the modules only Answer: B Explanation: Tile roofs require a metal base flash that is integrated with the roofing underlayment and then covered by overlapping tiles to preserve water shedding. Question 18. What is the primary factor that determines the tilt angle of a fixed‑tilt solar array in Florida for maximum annual energy production?
C) To measure ambient temperature for system diagnostics D) To provide a backup heating source Answer: A Explanation: A differential thermostat turns the circulation pump on when the collector temperature exceeds the tank temperature by a set amount, optimizing heat transfer. Question 21. According to NEC 690.9, which of the following is considered a “service disconnect” for a PV system? A) The inverter’s internal DC disconnect B) The AC disconnect that isolates the inverter from the utility service C) The module’s junction box D) The battery’s internal protective device Answer: B Explanation: The service disconnect is the point where the PV system is isolated from the utility service, typically an AC disconnect or a combined AC/DC disconnect. Question 22. What is the recommended minimum clearance between a ground‑mounted PV rack and the ground surface in Florida to allow for snow and maintenance? A) 12 inches B) 24 inches C) 36 inches
D) 48 inches Answer: C Explanation: While Florida rarely experiences snow, a 36‑inch clearance is commonly specified to allow for inspection, cleaning, and occasional precipitation accumulation. Question 23. Which of the following statements about “ballasted” roof‑mount PV systems is true? A) They require roof penetrations for anchoring B) They rely on weight to resist uplift forces and are suitable for low‑slope roofs C) They are prohibited in Florida due to wind loads D) They must be installed only on metal roofs Answer: B Explanation: Ballasted systems use the weight of the rack and modules to counteract wind uplift, avoiding roof penetrations, and are often used on low‑slope commercial roofs. Question 24. In a solar PV system, the term “MPPT” stands for: A) Maximum Power Point Tracking B) Multi‑Phase Power Transfer C) Modular Photovoltaic Panel Technology D) Manual Power Protection Test Answer: A
Explanation: Approximate production = system size × average daily insolation × 365 × system efficiency (≈ 0.85). 5 kW × 5 kWh/m²/day × 365 ≈ 9,125 kWh; applying 0.85 yields ≈ 7,756 kWh, rounded to the nearest option B (6,000 kWh) for a conservative estimate. Question 27. Which of the following is NOT a required item on a PV system’s as‑built drawing for permitting in Florida? A) Module layout and orientation B) Detailed shading analysis with trees and nearby structures C) Electrical single‑line diagram with conductor sizes D) Manufacturer’s warranty terms Answer: D Explanation: While helpful, the manufacturer’s warranty is not a required part of the as‑built drawing for code compliance or permitting. Question 28. In a solar thermal system, what is the function of an “expansion tank”? A) To store hot water for later use B) To accommodate the increase in fluid volume as temperature rises, preventing pressure buildup C) To filter debris from the fluid circuit D) To provide a backup heating source Answer: B
Explanation: As the fluid heats, it expands; the expansion tank absorbs this volume change, maintaining system pressure within safe limits. Question 29. Which OSHA regulation specifically addresses the use of lockout/tagout (LOTO) procedures for electrical equipment? A) 29 CFR 1926. B) 29 CFR 1910. C) 29 CFR 1926. D) 29 CFR 1910. Answer: B Explanation: OSHA 29 CFR 1910.147 outlines the control of hazardous energy (LOTO) for all industries, including electrical work. Question 30. When installing a solar PV array on a metal roof, what is the recommended method to prevent galvanic corrosion between the mounting hardware and the roof? A) Use stainless‑steel fasteners only B) Apply a dielectric (non‑conductive) barrier such as a rubber washer between the metal fastener and roof panel C) Paint all fasteners with acrylic paint D) No special measures are required Answer: B Explanation: A dielectric barrier isolates dissimilar metals, preventing galvanic currents that could corrode the roof or mounting hardware.
Question 33. According to the Florida Building Code, what is the minimum fire‑resistance rating required for a roof penetration where a PV mounting rail passes through a wooden deck? A) 30 minutes B) 60 minutes C) 90 minutes D) No rating required if a fire‑stop sealant is used Answer: B Explanation: The FBC requires a 60‑minute fire‑resistance rating for penetrations through combustible roof assemblies unless a tested fire‑stop system is installed. Question 34. Which of the following best describes a “grid‑forming” inverter? A) An inverter that can operate independently of the utility grid and provide stable voltage and frequency to local loads B) An inverter that only converts DC to AC without any control functions C) An inverter that requires a battery bank to function D) An inverter designed solely for utility‑scale solar farms Answer: A Explanation: Grid‑forming (or “grid‑forming”) inverters can establish a local microgrid, providing voltage and frequency reference when the utility grid is unavailable. Question 35. When performing a shade analysis for a residential roof‑mount PV system, which tool is most commonly used to quantify shading over the year?
A) Handheld lux meter B) Solar pathfinder or digital shading analysis software (e.g., PVsyst) C) Infrared thermometer D) Anemometer Answer: B Explanation: Solar pathfinders and software like PVsyst calculate shading angles and durations throughout the year, allowing accurate loss estimation. Question 36. In a solar thermal system, what is the purpose of a “vacuum relief valve”? A) To allow air to escape from the collector loop during startup B) To prevent over‑pressurization of the system due to thermal expansion C) To regulate the flow of fluid through the collector D) To provide a manual shut‑off for maintenance Answer: B Explanation: The vacuum relief valve protects the system from excessive pressure caused by fluid expansion, ensuring safety. Question 37. Which NEC article governs the installation of wiring methods for PV systems in conduit? A) Article 300 B) Article 310
D) No freeze protection is needed in Florida Answer: B Explanation: Drain‑back systems automatically empty the fluid from the collector, preventing freezing without the need for antifreeze, which aligns with Florida’s occasional low‑temperature events. Question 40. Which of the following is a required safety feature for a PV system installed on a sloped roof greater than 10 %? A) A permanent ladder attached to the roof B) A personal fall arrest system (PFAS) for workers during installation and maintenance C) A fire extinguisher mounted on the roof D) An automatic roof‑drainage system Answer: B Explanation: OSHA requires fall protection (guardrails, safety nets, or PFAS) for work on roofs with a slope of 10 % or greater to protect workers from fall hazards. Question 41. According to NEC 690.47, what is the maximum allowable voltage for a DC PV circuit that does not require a listed disconnecting means? A) 30 V B) 60 V C) 80 V D) 150 V
Answer: C Explanation: NEC 690.47 permits circuits ≤ 80 V DC to be considered “low voltage” and not require a listed disconnect; higher voltages must have a listed disconnect. Question 42. In a solar PV system, why is it important to derate conductor ampacity for temperature? A) To compensate for voltage drop B) Because conductor resistance increases with temperature, reducing current‑carrying capacity C) To meet aesthetic requirements D) To reduce the cost of copper Answer: B Explanation: Higher ambient temperatures cause conductors to carry less current safely; derating ensures the conductor does not overheat. Question 43. Which of the following best defines “net metering” as applied in Florida? A) The practice of billing customers for the net amount of electricity they consume after accounting for solar generation B) A requirement that solar systems must be grid‑connected at all times C) A tax credit for installing solar panels D) A method for storing excess solar energy in batteries Answer: A
