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CSLB C-46 Solar Contractor practice questions

207 free questions with answers and explanations.

Practice test
  1. 1.A solar installer is connecting a ground-mounted PV array to a central inverter. The array consists of multiple strings, each protected by an individual string fuse. Before connecting to the inverter's DC input, these strings are combined in a combiner box. What is the primary function of the blocking diode in this combiner box, if present?Photovoltaic System Installation
  2. 2.A solar technician is inspecting the electrical connections of a PV array after a strong windstorm. They notice several loose DC connectors on the roof. What is the most significant electrical hazard associated with loose DC connections in a PV system?Photovoltaic System Installation
  3. 3.An authorized employee is preparing to work on an energized 480V commercial solar inverter that is known to have exposed live parts. According to NFPA 70E, what is the MINIMUM approach distance (MAD) for unqualified persons to this equipment?Safety
  4. 4.A solar technician is troubleshooting a newly installed string inverter that is frequently disconnecting due to a 'Grid Undervoltage' error, even when the utility grid voltage appears stable. The system is operating at full power. What is the most likely cause of this issue?Photovoltaic System Installation
  5. 5.An electrical worker is about to install a new solar inverter in a commercial setting. The work involves connecting to an existing energized panel. Which of the following is the primary purpose of wearing arc-rated clothing?Safety
  6. 6.An installer is designing a PV system for a commercial building with a flat roof. The modules will be installed using a ballasted racking system. What is the primary reason for using ballast in this type of installation?Photovoltaic System Installation
  7. 7.A solar technician is performing a system startup for a new grid-tied PV system with microinverters. After all electrical connections are verified, what is the crucial final step before energizing the system and allowing it to produce power to the grid?Photovoltaic System Installation
  8. 8.A solar installer is connecting a new 7.6 kW string inverter to a 240V, 30A dedicated circuit breaker in the main service panel. The inverter's maximum continuous output current is 31.67A. According to NEC 690.8(A)(1) and 690.8(B)(1), what is the minimum continuous current rating the overcurrent protection device (OCPD) should have for this inverter output circuit?Photovoltaic System Installation
  9. 9.A solar installer is sizing the array for an off-grid PV system that needs to power a continuous load of 1500W at 24V DC for 8 hours per day. The system will use 300W PV modules, and the site has an average of 5 peak sun hours (PSH) per day. Assuming a system derate factor of 0.7, how many 300W PV modules are required?Photovoltaic System Installation
  10. 10.A solar installer is working on a sloped roof at a height of 15 feet. Which of the following fall protection measures is REQUIRED by OSHA for this scenario?Safety
  11. 11.A solar technician is working in an attic space that has not been properly ventilated. The technician experiences dizziness, headache, and nausea. Which hazardous material exposure is MOST likely causing these symptoms in this environment?Safety
  12. 12.A solar installer is connecting a new grid-tied string inverter to a residential service panel. The inverter has a maximum continuous output current of 25A. According to NEC 690.8(A)(1), what is the minimum required ampacity for the conductors carrying the inverter's AC output?Photovoltaic System Installation
  13. 13.A solar crew is installing modules on a residential roof. They need to access the roof using a portable ladder. What is the MINIMUM safe angle at which the base of the ladder should be placed relative to the wall?Safety
  14. 14.During the system startup of a new grid-tied PV installation, a solar technician notices that the inverter is repeatedly showing a 'Grid Out of Frequency' error and disconnecting. All AC wiring has been verified as correct. What is the most likely cause of this issue?Photovoltaic System Installation
  15. 15.A solar designer is laying out a rooftop PV system. The building has several vents and chimneys that will cause partial shading at different times of the day. To mitigate the impact of this partial shading on system performance, which of the following design strategies is most effective?Photovoltaic System Installation
  16. 16.A solar technician is performing a final inspection of a roof-mounted PV array. They notice that the module frames are not bonded to the racking system, and the racking system itself is not connected to the equipment grounding conductor (EGC). What is the primary safety concern with this improper grounding installation?Photovoltaic System Installation
  17. 17.A solar technician is working on a ladder near an energized circuit breaker panel. The technician is wearing rubber insulating gloves with leather protectors. What is the MAXIMUM voltage rating of the gloves that should be selected if the panel operates at 208V AC?Safety
  18. 18.A solar technician is installing a string inverter that requires dedicated AC overcurrent protection. The inverter's maximum continuous output current is 40A. According to the National Electrical Code (NEC), what is the MINIMUM standard overcurrent protection device (OCPD) rating required for this inverter circuit?Photovoltaic System Installation
  19. 19.A solar installer is connecting a new grid-tied string inverter to a residential service panel. According to NEC 690.8(A)(1), the inverter's maximum continuous output current is 28 Amperes. What is the minimum required ampacity for the conductors connecting the inverter's AC output to its overcurrent protective device?Photovoltaic System Installation
  20. 20.A solar designer is laying out a rooftop PV system where multiple small shading obstructions (e.g., vents, small satellite dishes) are present. To maximize energy harvest and minimize the impact of these obstructions, which type of power electronics should be specified?Photovoltaic System Installation
  21. 21.An electrical hazard assessment for a commercial solar installation reveals the potential for arc flash. Which of the following PPE categories, as defined by NFPA 70E, would be required for a task with an arc flash incident energy of 9 cal/cm²?Safety
  22. 22.A solar installer is exposed to direct sunlight for several hours while working on a roof. Which of the following is the MOST effective personal protective equipment (PPE) strategy to prevent heat-related illness and skin damage?Safety
  23. 23.A solar technician is installing a new PV array on a residential rooftop. Before connecting the DC strings to the inverter, they perform a polarity check on each string. They measure a positive voltage reading from the positive lead to the negative lead. What does this measurement indicate?Photovoltaic System Installation
  24. 24.A solar technician is troubleshooting a newly installed string inverter that is frequently reporting 'Grid Undervoltage' errors and shutting down. All AC and DC wiring has been verified as correct. What is the most likely cause of this issue?Photovoltaic System Installation
  25. 25.A solar installer is connecting a grid-tied PV system to a residential service panel. The system includes a string inverter with a maximum AC output current of 30A. The existing main service panel has a 200A busbar. According to NEC 705.12(B)(2), what is the maximum overcurrent protection device (OCPD) rating allowed for the PV inverter's AC output circuit if the main breaker is 200A?Photovoltaic System Installation
  26. 26.During a solar panel installation, a worker is required to use a portable generator to power tools. Before starting the generator, what is the MOST critical safety check related to electrical safety?Safety
  27. 27.A solar technician is performing a final inspection of a roof-mounted PV array before commissioning. They notice that the grounding conductor from the PV array frame is connected directly to a copper cold-water pipe on the roof. What is the primary concern with this grounding method?Photovoltaic System Installation
  28. 28.A solar technician is performing a ground fault test on a DC PV array. They measure the resistance between the positive DC conductor and ground, and then between the negative DC conductor and ground. Both readings show a very high resistance (e.g., >1 Mohm). What does this indicate?Photovoltaic System Installation
  29. 29.During a system commissioning, a solar technician observes that a newly installed string inverter is frequently disconnecting from the grid due to 'grid undervoltage' errors, even though the utility grid voltage appears stable. The AC circuit from the inverter to the service panel is a long run. What is the most probable cause of this issue?Photovoltaic System Installation
  30. 30.A solar installer is preparing to connect a string inverter to the AC service panel. They need to ensure that the inverter's AC output circuit is properly sized and protected. The inverter has a continuous output current of 25A at 240V. According to NEC 690.8(A)(1) and 690.8(B)(1), what is the minimum required ampacity for the conductors connecting the inverter to the AC service panel?Photovoltaic System Installation
  31. 31.A solar installer is connecting a new grid-tied string inverter to a residential service panel. The inverter has a maximum continuous output current of 28A at 240V. According to NEC 690.8(A)(1), what is the minimum required ampacity for the conductors connecting the inverter to the overcurrent protection device (OCPD)?Photovoltaic System Installation
  32. 32.A solar technician is working in an attic space where existing wiring is present. Before starting work, they notice some older, brittle wiring with cracked insulation. What is the immediate and most appropriate action the technician should take?Safety
  33. 33.A solar installer is connecting a ground-mounted PV array to a central inverter. The array is located a significant distance from the inverter, and the installer is concerned about potential reverse current flow from the inverter back into the array at night or during fault conditions. Which component is specifically designed to prevent this reverse current flow?Photovoltaic System Installation
  34. 34.A solar technician is inspecting the electrical connections of a PV array after a strong wind storm. They notice several loose connections at MC4 connectors. What is the most likely electrical hazard that could result from these loose connections?Photovoltaic System Installation
  35. 35.A solar installation crew is tasked with removing old roofing materials that contain asbestos. Before any work begins, what is the MOST critical administrative step that MUST be completed according to Cal/OSHA regulations for asbestos work?Safety
  36. 36.A solar technician is inspecting the electrical connections of a PV array after a strong wind storm. They notice visible burn marks and melted insulation around a DC connector between two modules. This type of damage is a strong indicator of what electrical fault?Photovoltaic System Installation
  37. 37.A solar technician is inspecting a residential PV system and notices that the overcurrent protection device (OCPD) for a string inverter is rated significantly higher than the inverter's maximum continuous output current. What is the primary safety concern with this setup?Safety
  38. 38.A solar crew is working on a residential rooftop where the roof pitch is 8:12. The eave height is 12 feet from the ground. What is the minimum height above the eave that a ladder must extend to safely access the roof?Safety
  39. 39.During a rooftop solar installation, a worker accidentally drops a heavy tool that slides off the roof edge. There are workers below. What type of PPE or safety measure is specifically designed to protect workers on the ground from falling objects?Safety
  40. 40.A solar designer is laying out a rooftop PV system. The building has several vents and chimneys that will cast shadows on the array at various times of the day. To mitigate the impact of partial shading, which of the following system configurations is generally MOST effective?Photovoltaic System Installation
  41. 41.A solar designer is planning a large commercial PV installation on a flat membrane roof. To optimize energy production and minimize roof penetrations, they opt for a ballasted racking system. What is the primary method used to prevent the array from being dislodged by wind uplift in this type of system?Photovoltaic System Installation
  42. 42.A solar technician is installing a string inverter that requires dedicated AC overcurrent protection. The inverter's continuous output current rating is 20A. According to NEC 690.8(A)(1) and 690.9(A), what is the minimum standard overcurrent protection device (OCPD) rating required for this inverter's AC output circuit?Photovoltaic System Installation
  43. 43.A solar technician is performing a visual inspection of a PV array. They observe significant discoloration and browning around the edges of several PV cells within multiple modules, particularly in areas prone to moisture. This condition, often accompanied by reduced power output, is most likely indicative of what type of degradation?Photovoltaic System Installation
  44. 44.A solar technician is installing a new PV array on a commercial flat roof. The design calls for a non-penetrating ballasted racking system. What is the primary method used to ensure the array's stability against wind uplift forces?Photovoltaic System Installation
  45. 45.A solar technician is performing a final inspection of a roof-mounted PV array before commissioning. They notice that the module frames are not bonded to the equipment grounding conductor. Which NEC requirement is being violated?Photovoltaic System Installation
  46. 46.A solar contractor is preparing to connect a new PV system to the existing main service panel of a residence. The service panel has a 200A main breaker and a busbar rating of 200A. The new PV inverter has a 40A output circuit breaker. According to NEC 705.12(B)(2) (the 120% rule), what is the MAXIMUM allowable continuous current for this PV system's connection to the busbar without requiring an upgrade to the service panel?Photovoltaic System Installation
  47. 47.A solar installation team is performing a system startup on a new 10 kW residential PV array using microinverters. After connecting all AC and DC wiring, what is the CRITICAL first step to energize the system safely and correctly?Photovoltaic System Installation
  48. 48.A solar installer is connecting a charge controller to a battery bank for an off-grid PV system. The battery bank consists of four 12V batteries connected in series. The charge controller is rated for a maximum input voltage of 150V and a maximum charge current of 60A. What is the total nominal voltage of the battery bank?Photovoltaic System Installation
  49. 49.A solar technician is performing a ground continuity test on a newly installed PV array. They measure the resistance between the module frames and the main grounding electrode conductor (GEC). What is the maximum allowable resistance for this connection to be considered adequately grounded, according to common industry standards and best practices for safety?Photovoltaic System Installation
  50. 50.A solar crew is about to begin work on a rooftop where an existing HVAC unit's disconnect switch is located. The HVAC unit is not part of the solar installation, but its circuit is adjacent to the work area. To comply with Lockout/Tagout (LOTO) procedures, what is the FIRST step the authorized employee should take?Safety