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CSLB C-46 Solar Contractor practice questions

207 free questions with answers and explanations.

Practice test
  1. 51.A solar technician is performing a system startup for a new grid-tied PV system with microinverters. After verifying all AC and DC connections, what is the critical next step before closing the AC disconnect and allowing the system to energize the grid?Photovoltaic System Installation
  2. 52.A solar technician is working on a rooftop PV system and needs to access modules that are several feet beyond their reach from a securely positioned extension ladder. To avoid overreaching, what is the safest and most compliant action the technician should take?Safety
  3. 53.A solar technician is performing a ground continuity test on a newly installed PV array. They are using a multimeter to check the resistance between the module frames, racking system, and the main grounding electrode conductor. What is the acceptable resistance reading for a properly grounded PV system?Photovoltaic System Installation
  4. 54.A solar crew is installing modules on a flat commercial roof. The work area is close to the edge of the roof (within 6 feet) and there is no parapet wall. What is the MOST appropriate fall protection system required by Cal/OSHA for this scenario?Safety
  5. 55.A solar technician is inspecting the electrical connections of a PV array. They observe that some module connectors are not fully seated, and the locking mechanisms are not engaged. What is the MOST significant risk associated with these improperly connected DC connectors?Photovoltaic System Installation
  6. 56.A solar designer is laying out a rooftop PV system. The building has several vents and chimneys that will cause intermittent shading on portions of the array at different times of the day. To optimize energy production under these conditions, which component is most effective at mitigating the effects of partial shading on individual modules?Photovoltaic System Installation
  7. 57.A solar installer is commissioning a new grid-tied PV system. During the final inspection, they notice that the main service panel has a 200A busbar. The existing main breaker is 200A, and the new PV breaker being added is 40A. According to NEC 705.12(B)(2) for supply-side connections, what is the maximum allowable PV system output current that can be connected to this busbar without requiring an upgrade?Photovoltaic System Installation
  8. 58.A solar installer is mounting PV modules onto a flat commercial roof using a ballasted racking system. What is the primary method used to prevent the array from being uplifted by high winds?Photovoltaic System Installation
  9. 59.A solar technician is troubleshooting an off-grid PV system with a battery bank. They notice that the battery bank is not charging, despite the PV array producing sufficient power. Upon inspection, they find that the charge controller is showing an error code related to reverse polarity on the battery connection. Which of the following is the most immediate and critical action to take?Photovoltaic System Installation
  10. 60.A solar technician is performing a pre-commissioning inspection of a newly installed grid-tied PV system. They notice that the DC disconnect switch is labeled 'NOT LOAD BREAK RATED'. What is the primary implication of this label?Photovoltaic System Installation
  11. 61.A solar installer is configuring a string inverter system for a residential rooftop. The system consists of 18 photovoltaic modules, each with a nominal voltage of 30V and a nominal current of 9A. The selected string inverter has a maximum DC input voltage of 600V and a maximum input current per MPPT tracker of 15A. What is the maximum number of modules that can be connected in series per string without exceeding the inverter's maximum input voltage, assuming standard operating conditions?Photovoltaic System Installation
  12. 62.A solar installer is using a portable electric circular saw on a job site. Which of the following electrical safety features is REQUIRED by OSHA for this tool to protect against electrical shock?Safety
  13. 63.A solar technician is about to use a portable electric drill on a job site. Which of the following is the most critical safety feature or practice to ensure protection against electric shock?Safety
  14. 64.A solar technician is inspecting a rooftop array and notices that the grounding electrode conductor (GEC) for the main service panel appears to be corroded at the connection point to the grounding electrode. What is the MOST immediate and significant safety concern associated with this condition?Safety
  15. 65.A solar designer is creating a system layout for a residential rooftop with multiple small obstructions (e.g., vents, chimneys). To maximize energy harvest and minimize the impact of partial shading, what is the most effective inverter technology to specify?Photovoltaic System Installation
  16. 66.During the final inspection of a newly installed PV system, a solar contractor observes that the DC combiner box is mounted directly to the roof decking without any standoffs, allowing no air circulation behind it. What code violation or potential issue does this practice present?Photovoltaic System Installation
  17. 67.A solar crew is installing modules on a steep commercial roof that requires the use of a ladder to access the work area. The base of the ladder is placed 10 feet from the wall. What is the ideal working length of the ladder to maintain the safest angle?Safety
  18. 68.A solar technician is inspecting a PV array and notices a significant drop in power output from a specific string. Upon testing, they find that the open-circuit voltage (Voc) of the string is normal, but the short-circuit current (Isc) is significantly reduced. Which of the following conditions is the most likely cause?Photovoltaic System Installation
  19. 69.A solar technician is inspecting the electrical wiring of a PV array on a commercial rooftop. They notice several DC homerun conductors are routed through an open metal conduit exposed to direct sunlight. What is the primary risk associated with this installation practice?Photovoltaic System Installation
  20. 70.A solar technician is working on a commercial roof with a significant amount of bird droppings and dust. Which of the following respiratory protection is MOST appropriate for preventing inhalation hazards in this environment?Safety
  21. 71.During a system commissioning, a solar technician observes that a newly installed string inverter is frequently cycling on and off, displaying a 'High Grid Voltage' error. The utility grid voltage appears stable and within normal limits at the service entrance. What is the MOST likely cause of this inverter behavior?Photovoltaic System Installation
  22. 72.A solar technician is performing an open-circuit voltage (Voc) test on a PV array string. They measure 450V, but the inverter specification requires a maximum Voc of 400V. Which of the following is the most appropriate action to take to bring the string within the inverter's specifications?Photovoltaic System Installation
  23. 73.A solar installer is connecting a new 7.6 kW string inverter to a 240V, 30A dedicated circuit in a residential service panel. According to NEC 690.8(A)(1), what is the minimum required ampacity for the conductors connecting the inverter's AC output to the overcurrent protective device?Photovoltaic System Installation
  24. 74.A solar technician is working on a residential rooftop where the slope is 7:12. The roof surface is dry, and the technician is wearing appropriate non-slip footwear. What is the minimum fall protection requirement according to Cal/OSHA for this scenario?Safety
  25. 75.A solar technician is required to work on an energized 600V DC combiner box for diagnostic purposes. Which type of insulating gloves should the technician use to ensure adequate protection against electric shock?Safety
  26. 76.A solar contractor is installing a ground-mounted PV system on a sloped terrain. To ensure optimal energy production throughout the year, what is the primary factor to consider when determining the tilt angle of the PV modules in a fixed-tilt system in California?Photovoltaic System Installation
  27. 77.A solar technician is inspecting a PV array and notices a significant drop in power output from one string. Upon further investigation, they find that a portion of the string's modules is heavily shaded by a newly grown tree. How does this partial shading primarily affect the string's overall current (Isc)?Photovoltaic System Installation
  28. 78.A solar installer is working on a commercial rooftop when they encounter a drum labeled with a corrosive hazard symbol and 'Sodium Hydroxide'. The drum appears to be leaking slightly. What is the IMMEDIATE and most appropriate action the installer should take?Safety
  29. 79.A homeowner reports that their newly installed grid-tied PV system is not producing power, despite clear skies. The inverter display shows a 'Grid Fault' error code. The utility grid is confirmed to be operational. Which of the following is the MOST likely cause of this error?Photovoltaic System Installation
  30. 80.A solar technician is working in a confined space, such as an underground utility vault, to connect a new solar array to the grid. Prior to entry, the atmosphere was tested and found to be oxygen deficient. What is the most appropriate next step before allowing entry?Safety
  31. 81.A solar designer is planning a PV system for a residential building with a complex roof layout, featuring multiple small shading obstructions (e.g., chimneys, vents, dormers) at different times of the day. Which type of power electronics would be most effective at maximizing energy harvest in this scenario?Photovoltaic System Installation
  32. 82.A solar technician is installing a new PV array on a residential rooftop. Before connecting the DC strings to the inverter, they need to verify the polarity of each string to prevent damage to the equipment. Which instrument is most appropriate for this task?Photovoltaic System Installation
  33. 83.A solar technician is installing an off-grid PV system with a battery bank. To prevent reverse current flow from the battery bank back into the PV array at night, which component is essential and typically integrated into the charge controller or PV combiner box?Photovoltaic System Installation
  34. 84.A solar technician is performing system startup on a new PV installation. After all electrical connections are made and verified, what is the final step before closing the AC disconnect and allowing the inverter to energize the grid?Photovoltaic System Installation
  35. 85.A solar technician is performing an open-circuit voltage (Voc) test on a PV array string. The measured Voc is significantly lower than the expected value based on the module specifications and temperature. Which of the following is the MOST likely cause for this discrepancy?Photovoltaic System Installation
  36. 86.A solar contractor is installing a new solar water heating system. The system's expansion tank is designed to absorb thermal expansion of the potable water. According to the Uniform Plumbing Code (UPC) and California Plumbing Code (CPC), where should the expansion tank typically be installed in relation to the water heater?Electrical and Plumbing Codes
  37. 87.A solar contractor is installing a new solar thermal system on a commercial building. The system uses a non-potable heat transfer fluid and includes an expansion tank. According to the California Plumbing Code (CPC), an expansion tank for a non-potable closed-loop system must be installed such that it is accessible for inspection and replacement. What is the maximum permitted working pressure of such an expansion tank, relative to the system's working pressure?Electrical and Plumbing Codes
  38. 88.A solar contractor is installing a new solar water heating system for a residential application. The system uses a potable water storage tank and includes a temperature and pressure (T&P) relief valve. According to the California Plumbing Code (CPC), the discharge pipe from the T&P relief valve must be installed to allow complete visual inspection of the flow. What is the maximum height above the receptor to which the discharge pipe can terminate?Electrical and Plumbing Codes
  39. 89.A solar contractor is designing a PV system for a single-family dwelling that will include a rapid shutdown system. According to NEC Article 690.12, what is the maximum permissible time for the controlled conductors outside the array to be reduced to no more than 30 volts and 240 volt-amperes after initiation of the rapid shutdown function?Electrical and Plumbing Codes
  40. 90.A solar contractor is installing a battery energy storage system (BESS) as part of a hybrid PV installation in a commercial building. According to the National Electrical Code (NEC), what is the minimum required working clearance in front of the BESS if it contains uninsulated live parts that require examination, adjustment, servicing, or maintenance while energized?Electrical and Plumbing Codes
  41. 91.A solar contractor is planning the DC wiring for a new ground-mounted PV array. The array will consist of multiple strings, each operating at 400 VDC. The contractor needs to ensure that the overcurrent protection device (OCPD) for each string is appropriately sized. According to the National Electrical Code (NEC), what is the minimum continuous current rating for the OCPD protecting the PV array conductors?Electrical and Plumbing Codes
  42. 92.A solar contractor is installing a new solar thermal system on a commercial building. The system includes a closed-loop, non-potable heat transfer fluid. According to the California Plumbing Code (CPC), what is the minimum required separation distance between the non-potable fluid piping and any potable water piping?Electrical and Plumbing Codes
  43. 93.A solar contractor is installing a new solar thermal system for domestic hot water. The system includes a storage tank that will be supplied by the municipal water main. According to the California Plumbing Code (CPC), what is the maximum pressure relief valve setting for a potable water heater, unless otherwise specified by the manufacturer?Electrical and Plumbing Codes
  44. 94.A solar contractor is installing a ground-mounted PV array on a commercial property. The array structure will be constructed using galvanized steel. According to the National Electrical Code (NEC), what is the minimum acceptable method for bonding the non-current-carrying metal parts of the PV array structure to ensure proper grounding?Electrical and Plumbing Codes
  45. 95.A solar contractor is installing a ground-mounted PV array on a commercial property. The metallic support structure for the array is required to be bonded. According to the National Electrical Code (NEC), what is the minimum size of the equipment grounding conductor (EGC) for the PV array structure if the PV system's maximum overcurrent protective device (OCPD) is 100 amperes?Electrical and Plumbing Codes
  46. 96.A solar contractor is installing a PV array on a commercial building rooftop. The DC PV source circuit conductors are run in metallic conduit along the roof surface. The conduit is exposed to direct sunlight. According to NEC Article 310.15(B)(2)(a), what is the minimum temperature adder that must be applied to the ambient temperature when calculating conductor ampacity for conduits exposed to direct sunlight on or above rooftops?Electrical and Plumbing Codes
  47. 97.A solar contractor is installing a grid-tied PV system on a commercial building. The inverter for the system has a maximum continuous output current of 50 amperes. The feeder circuit supplying the PV system disconnect is protected by a 100-ampere overcurrent protective device. According to the National Electrical Code (NEC), what is the maximum allowable continuous current for the PV system's AC output circuit conductors before applying any adjustment or correction factors?Electrical and Plumbing Codes
  48. 98.A solar contractor is installing a conduit containing PV array circuit conductors on a rooftop. The conduit is exposed to direct sunlight and high ambient temperatures. According to NEC Article 310.15(B)(2)(c), what additional temperature adder must be applied to the ambient temperature for conduits exposed to direct sunlight on or above a rooftop, when the conduit is less than 7/8 inch from the roof surface?Electrical and Plumbing Codes
  49. 99.A solar installer is commissioning a new PV system. The homeowner asks about the purpose of the readily accessible, lockable, and labeled PV system disconnecting means. Which of the following best describes its primary function according to the National Electrical Code (NEC)?Electrical and Plumbing Codes
  50. 100.A solar contractor is installing a grid-tied PV system on a commercial building. The system includes multiple string inverters that are connected to a common AC combiner panel. The local utility requires a visible, lockable, and readily accessible AC disconnecting means for the PV system. According to NEC Article 690.15, where must this AC disconnecting means be located?Electrical and Plumbing Codes