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CSLB C-46 Solar Contractor practice questions

207 free questions with answers and explanations.

Practice test
  1. 101.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
  2. 102.A solar contractor is planning the installation of a new rooftop PV system for a residential client. The system will be connected to the supply side of the existing service equipment. According to the National Electrical Code (NEC), what is the maximum permissible distance from the utility service conductors for the PV supply-side connection?Electrical and Plumbing Codes
  3. 103.A solar contractor is calculating the maximum current for PV source circuits within a PV array. The PV modules have a short-circuit current (Isc) of 9.2 A. The array will be installed in an area with an ambient temperature that can reach 40°C. According to NEC Article 690.8(A)(1), what is the maximum circuit current (Imc) for these PV source circuits, before applying any continuous load multipliers?Electrical and Plumbing Codes
  4. 104.A solar installer is connecting a PV system to an existing residential service. The main service panel has a 200A busbar. The main overcurrent protective device (OCPD) is rated at 200A. The PV inverter output circuit breaker is rated at 40A. Using the 120% rule for load-side connections (NEC 705.12(B)(2)(3)), what is the maximum allowable continuous current rating of the PV inverter output circuit breaker that could be connected to this busbar without requiring an upgrade to the busbar or main OCPD?Electrical and Plumbing Codes
  5. 105.A solar contractor is installing a new residential PV system. The system's inverter has an output circuit rated for 30 amperes. According to the National Electrical Code (NEC), what is the minimum required size for the equipment grounding conductor (EGC) for this circuit if it's run in a conduit with a 75°C rated conductor?Electrical and Plumbing Codes
  6. 106.A solar installer is planning a rooftop photovoltaic (PV) system installation for a residential property. The system includes a main service panel, a PV inverter, and a dedicated PV disconnect switch. According to the California Electrical Code (CEC), what is the maximum permitted length of the supply-side PV output circuit conductors from the PV disconnect to the service disconnecting means before overcurrent protection is required at the point of connection?Electrical and Plumbing Codes
  7. 107.A solar contractor is installing a hybrid PV system that includes a battery energy storage system (BESS). The BESS is located in a dedicated utility room. According to NEC Article 706.7(C), what is the minimum required working clearance in front of the battery system where there are exposed live parts or components that may require examination, adjustment, servicing, or maintenance while energized?Electrical and Plumbing Codes
  8. 108.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
  9. 109.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
  10. 110.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
  11. 111.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
  12. 112.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
  13. 113.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
  14. 114.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
  15. 115.A C-46 contractor is designing a commercial rooftop PV system on a building with a flat, asphalt-covered roof. The structural engineer has specified a maximum distributed load limit of 5 pounds per square foot (psf) for the PV array. Which of the following racking systems would be MOST appropriate to stay within this structural limit while minimizing roof penetrations?Planning and Estimating
  16. 116.A C-46 contractor is developing a project schedule for a commercial solar installation. The project involves multiple subcontractors (roofing, electrical, PV installation) and requires several inspections. Which project management tool would be MOST effective for visualizing task dependencies, critical path, and overall project timeline?Planning and Estimating
  17. 117.A solar thermal installer is commissioning a new closed-loop glycol system. During the startup, the installer notices that the pump runs continuously, but the collector outlet temperature is consistently much lower than expected, even on a sunny day. The storage tank temperature is also not rising significantly. Which of the following is the most likely cause?Solar Thermal System Installation
  18. 118.A solar thermal installer is troubleshooting a closed-loop glycol system where the circulating pump often short cycles, turning on and off rapidly, even when there's a significant temperature difference between the collector and the storage tank. What is the most probable cause for this short cycling behavior?Solar Thermal System Installation
  19. 119.A solar thermal system uses an immersion-type temperature sensor for the storage tank. When troubleshooting, an installer finds that the sensor is providing erratic readings. Which of the following is the most likely cause of erratic readings for an immersion sensor?Solar Thermal System Installation
  20. 120.A C-46 contractor is preparing an estimate for a residential PV system. The client has specifically requested a system that can provide partial power during grid outages without relying on batteries. Which of the following inverter types would be MOST suitable for this requirement?Planning and Estimating
  21. 121.A C-46 contractor is conducting a final inspection of a newly installed residential PV system before calling for the rough-in electrical inspection. Which of the following is the MOST critical item to verify regarding grounding and bonding for system safety?Planning and Estimating
  22. 122.During the startup of a new solar thermal system, the installer observes that the circulation pump frequently cycles on and off, even under stable solar conditions and a consistent temperature difference between the collector and storage. What is the MOST likely cause of this 'short cycling' behavior?Solar Thermal System Installation
  23. 123.A C-46 contractor is preparing a bid for a large commercial PV installation. The client is very cost-sensitive and has provided a detailed list of desired performance metrics. To ensure the bid is competitive while meeting performance expectations, which of the following estimating strategies would be MOST effective?Planning and Estimating
  24. 124.A C-46 contractor is preparing a preliminary design for a large commercial rooftop PV system. The building has significant existing HVAC equipment and other obstructions, leading to complex shading patterns throughout the day. Which of the following system design approaches would be MOST effective in mitigating the impact of partial shading on overall system performance?Planning and Estimating
  25. 125.A solar thermal installer is integrating a new pumped closed-loop system with an existing domestic hot water (DHW) storage tank that has an unused heat exchanger coil. The installer must ensure that the non-potable heat transfer fluid (glycol) in the solar loop does not contaminate the potable water supply. Which of the following heat exchanger configurations is required by code for this application?Solar Thermal System Installation
  26. 126.A solar thermal system installer is connecting a new collector array to the existing piping. The local plumbing code specifies that all piping within 5 feet of the collector must be rated for continuous exposure to temperatures up to 350°F (177°C) and pressure up to 150 psi. Which of the following pipe materials is most appropriate for this application?Solar Thermal System Installation
  27. 127.A solar thermal system installer is positioning a flat-plate collector on a sloped roof. To ensure proper drainage and prevent air pockets, what is the MINIMUM recommended pitch for a horizontal collector header?Solar Thermal System Installation
  28. 128.A solar thermal installer is integrating a new domestic hot water (DHW) system with an existing conventional water heater. The solar pre-heat tank needs to be plumbed in series with the conventional heater. What is the correct piping configuration to maximize solar contribution?Solar Thermal System Installation
  29. 129.A C-46 contractor is designing a solar PV system for a commercial building with multiple roof sections. The building owner wants to maximize energy production and future-proof the system. What is the primary benefit of using Module-Level Power Electronics (MLPE) like microinverters or power optimizers in this scenario?Planning and Estimating
  30. 130.A solar thermal installer is connecting a circulation pump to the electrical supply for a 240V, 60Hz system. The pump's nameplate indicates it draws 0.75 Amps and has a power factor of 0.85. What is the apparent power (VA) of this pump?Solar Thermal System Installation
  31. 131.A solar thermal system installer is connecting the circulating pump to the electrical supply. The pump is rated for 120V AC and draws 1.5 Amperes. Assuming a power factor of 0.8, what is the apparent power consumed by the pump?Solar Thermal System Installation
  32. 132.A C-46 contractor is designing a commercial rooftop PV system. The client's electrical panel is located on the opposite side of the building from the ideal array location, requiring a long conduit run. What is the primary consideration when sizing the conductors for this long run?Planning and Estimating
  33. 133.A C-46 contractor is preparing a bid for a new residential PV installation. The client is highly budget-conscious but still wants a reliable system. The contractor is considering options to reduce the overall project cost without compromising safety or significant performance. Which of the following approaches is an example of 'value engineering' in this context?Planning and Estimating
  34. 134.A C-46 contractor is conducting a preliminary site assessment for a new residential PV installation. The homeowner expresses concern about the aesthetic impact of conduit running across the exterior of their newly painted stucco home. Which of the following is the MOST effective planning consideration to address this aesthetic concern while maintaining code compliance?Planning and Estimating
  35. 135.A C-46 contractor is designing a grid-tied PV system for a residential client. The client's average daily energy consumption is 20 kWh. Assuming 5 peak sun hours per day and a system derate factor of 0.77, what is the approximate DC array size required to meet 100% of the client's energy needs?Planning and Estimating
  36. 136.A solar thermal system installer needs to ensure that the heat transfer fluid in a closed-loop system will not freeze in winter conditions. The system uses propylene glycol. What is the MOST reliable method to verify the freeze protection level of the glycol solution in the field?Solar Thermal System Installation
  37. 137.A C-46 contractor is performing a site analysis for a residential PV system. The client's roof has multiple dormers and vents, creating numerous small, shaded areas throughout the day. To maximize energy harvest from each module independently and mitigate the effects of partial shading, which component combination is most appropriate for the system design?Planning and Estimating
  38. 138.A solar thermal installer is determining the optimal tilt angle for a flat-plate collector array for a domestic hot water system in a residential application in California (latitude approximately 34°N). The primary goal is to maximize annual energy collection. Which of the following tilt angles is generally recommended?Solar Thermal System Installation
  39. 139.A solar thermal installer is troubleshooting a closed-loop glycol system that is experiencing frequent overheating and stagnation, even with adequate solar radiation. The differential controller appears to be functioning correctly, but the pump is not circulating fluid as expected. What is the MOST likely cause of this issue?Solar Thermal System Installation
  40. 140.A solar contractor is planning a grid-tied residential PV system. The client's average daily energy consumption is 25 kWh. The site receives an effective 5.5 sun-hours per day, and the system's derate factor is estimated to be 0.75. What is the minimum DC array size (in kW) required to meet 100% of the client's energy needs?Planning and Estimating
  41. 141.A solar thermal system is being installed on a sloped residential roof with a pitch of 7:12. The local building code requires that all collector arrays have a minimum standoff height of 3 inches from the roof surface to allow for air circulation and prevent moisture buildup. Which of the following mounting methods would NOT meet this requirement without additional modification?Solar Thermal System Installation
  42. 142.A C-46 contractor is designing a commercial PV system for a building with a large, unobstructed flat roof. The client wants to maximize the number of modules installed while adhering to fire code setbacks and minimizing row-to-row shading. The optimal tilt angle for the modules is 10 degrees. What is the MOST critical factor to consider when determining the spacing between module rows?Planning and Estimating
  43. 143.A solar contractor is preparing a bid for a large commercial PV project. The project specifications require a detailed bill of materials (BOM), labor estimates for each installation phase, and a breakdown of soft costs. Which of the following components would be classified as a 'soft cost' in this project estimate?Planning and Estimating
  44. 144.A C-46 contractor is performing a site analysis for a PV installation on a single-family home. The homeowner expresses strong concerns about the aesthetics of visible conduit runs on the exterior of their home. Which of the following conduit routing strategies would be MOST effective in addressing the homeowner's aesthetic concerns?Planning and Estimating
  45. 145.A solar thermal installer is troubleshooting a system where the collector fluid is getting very hot, but the storage tank temperature is not increasing sufficiently. The pump is running, and there are no obvious leaks or air binding. What component should the installer suspect as the MOST likely cause of inefficient heat transfer?Solar Thermal System Installation
  46. 146.A solar thermal system installer is preparing to pressure test a newly installed closed-loop glycol system. The system has a maximum operating pressure of 50 psi. According to industry best practices and common code requirements, what is the recommended minimum test pressure for this system?Solar Thermal System Installation
  47. 147.When performing system design for a residential PV installation, the National Electrical Code (NEC) article 690.7 requires that maximum system voltage (Vmp) for a PV array does not exceed a certain limit for one- and two-family dwellings. What is this maximum DC voltage limit?Planning and Estimating
  48. 148.A solar contractor is preparing the final system design for a residential PV array. The design includes a string inverter and multiple strings of modules. To ensure proper operation and prevent potential damage to the inverter, what critical parameter must be carefully matched between the PV array and the string inverter?Planning and Estimating
  49. 149.A C-46 contractor is evaluating different mounting solutions for a flat commercial roof that has limited structural capacity. The client is concerned about potential roof membrane penetrations and wants to minimize additional weight. Which racking system type would be most suitable for this scenario?Planning and Estimating
  50. 150.A solar thermal system with a differential controller is ready for startup. The installer observes that the pump is running, but the collector temperature (Tc) is 120°F and the storage tank bottom temperature (Ts) is 130°F. The differential ON setting is 15°F and the differential OFF setting is 5°F. What is the most likely reason for the pump running under these conditions?Solar Thermal System Installation