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CSLB C-46 Solar Contractor practice questions

207 free questions with answers and explanations.

Practice test
  1. 151.During a site analysis for a residential PV installation, a C-46 contractor observes significant shading from a large, mature tree to the east of the primary roof plane. This shading occurs consistently during the early morning hours. What is the most effective immediate action the contractor should take regarding this specific shading issue?Planning and Estimating
  2. 152.A homeowner reports that their solar thermal domestic hot water system is producing lukewarm water, even on sunny days. The system uses an open-loop thermosiphon design. Which of the following is the most likely cause for this issue?Solar Thermal System Installation
  3. 153.A solar contractor is designing a commercial PV system for a building with a flat roof. The structural engineer's report indicates limited load capacity, requiring a lightweight racking solution. Which of the following racking system types would be MOST suitable for this constraint?Planning and Estimating
  4. 154.A solar thermal system is being filled with a propylene glycol solution. After initial filling and venting, the installer performs a pressure test. The system holds pressure for 30 minutes with no visible leaks. What is the next critical step before fully commissioning the system?Solar Thermal System Installation
  5. 155.A solar thermal installer is preparing to pressure test a newly installed closed-loop glycol system. What is the minimum pressure a solar thermal system should be tested to, relative to its operating pressure?Solar Thermal System Installation
  6. 156.A C-46 contractor is preparing an estimate for a ground-mounted PV system. The site requires extensive trenching for DC and AC conductor runs from the array to the inverter and main service panel. Which of the following is the most significant cost driver for this specific part of the project?Planning and Estimating
  7. 157.A C-46 contractor is developing a project plan for a large commercial PV installation. The project involves multiple subcontractors for roofing, electrical, and structural work. To effectively manage timelines, dependencies, and critical path activities, which project management tool is most appropriate?Planning and Estimating
  8. 158.A solar contractor is developing a project plan for a complex commercial rooftop installation. The project requires coordination with multiple subcontractors, a tight timeline, and strict budget constraints. Which project management tool is BEST suited for visualizing task dependencies, critical path, and overall project schedule?Planning and Estimating
  9. 159.A solar thermal system with an open-loop drainback configuration is being designed for a commercial building. What is a critical design consideration for the collector array piping in this type of system that differs from a closed-loop system?Solar Thermal System Installation
  10. 160.A solar thermal system installer is replacing an old pump with a new one in a closed-loop system. After installation, the installer notices excessive noise and vibration originating from the pump. Which of the following is the MOST likely cause of this issue?Solar Thermal System Installation
  11. 161.A solar thermal system installer is using a multimeter to check the resistance of a thermistor used as a collector temperature sensor. The multimeter reads 10,000 ohms at 25°C. If the collector temperature increases, how should the resistance reading change for a Negative Temperature Coefficient (NTC) thermistor?Solar Thermal System Installation
  12. 162.A C-46 contractor is performing a site analysis for a ground-mounted PV system. The client wants to maximize energy production throughout the year. The site is located in California at approximately 34 degrees North latitude. What would be the MOST appropriate tilt angle for the PV array?Planning and Estimating
  13. 163.A C-46 contractor is assessing a potential site for a ground-mounted PV system. The site has significant mature trees to the south, east, and west, which will cause substantial shading during different parts of the day and year. Removing the trees is not an option. Which of the following strategies would be MOST effective to mitigate the impact of this extensive shading?Planning and Estimating
  14. 164.A homeowner reports that their newly installed solar thermal system is producing domestic hot water, but the temperature is consistently lower than expected, even on sunny days. The system uses an active closed-loop design with a flat-plate collector. What is the MOST likely cause of this underperformance?Solar Thermal System Installation
  15. 165.A solar thermal installer is performing the initial fill of a closed-loop propylene glycol system. After filling the system and purging air, the installer needs to verify the freeze protection level of the glycol solution. What is the most accurate and common method to determine the freeze protection temperature of the glycol solution in the field?Solar Thermal System Installation
  16. 166.During the initial site analysis for a residential solar installation, a contractor observes significant shading on the roof from a large, mature oak tree to the southwest. Which of the following is the MOST appropriate initial action to address this observation?Planning and Estimating
  17. 167.During the system design phase, a contractor is evaluating inverter options for a residential PV system. The client wants to maximize self-consumption and has an electric vehicle (EV) charger. Which type of inverter would be MOST beneficial for integrating energy storage and smart home energy management features?Planning and Estimating
  18. 168.A C-46 contractor is preparing an estimate for a residential PV system. The client has specifically requested a system that can provide backup power during grid outages. Which of the following components would be a necessary addition to a standard grid-tied PV system to meet this requirement?Planning and Estimating
  19. 169.A C-46 contractor is performing a site analysis for a commercial building. The building has a flat roof, and the client wants to install a PV array that is easily accessible for cleaning and maintenance without compromising roof integrity. What is a critical factor to consider when determining the optimal tilt angle and row spacing for the array on this flat roof?Planning and Estimating
  20. 170.A C-46 contractor is developing a project plan for a large commercial PV installation. The project involves multiple subcontractors, complex logistics, and a strict deadline for interconnection. To effectively manage the sequence of tasks, identify critical paths, and allocate resources, which project management tool is most suitable?Planning and Estimating
  21. 171.A C-46 contractor is preparing an estimate for a residential grid-tied PV system. The client has specifically requested a system that can provide critical load backup during grid outages, but with minimal additional cost beyond the standard PV installation. Which inverter technology best meets this requirement?Planning and Estimating
  22. 172.A C-46 contractor is performing a site analysis for a residential rooftop PV system. During the inspection, they identify several existing penetrations (e.g., plumbing vents, chimneys, skylights) that will significantly constrain the available unshaded roof space. The client insists on maximizing system size within the available area. Which design approach is most effective for this scenario?Planning and Estimating
  23. 173.A C-46 contractor is designing a commercial rooftop PV system for a building with a flat, unused roof. The client wants to maximize energy production while ensuring the long-term integrity of the roof membrane. The preliminary site analysis indicates the roof has sufficient structural capacity but a limited load capacity for additional ballast. Which racking system would be most appropriate for this scenario?Planning and Estimating
  24. 174.A C-46 contractor is preparing an estimate for a residential PV system. The client is interested in minimizing the visual impact of the array on the front-facing roof plane of their aesthetically sensitive home. The jurisdiction allows for flush-mounted systems. Which design consideration is most critical for achieving this aesthetic goal?Planning and Estimating
  25. 175.A C-46 contractor is performing a site analysis for a ground-mounted PV system on a large, undeveloped rural lot. The client's primary objective is to maximize the system's annual energy production while minimizing the Levelized Cost of Electricity (LCOE). The site has no significant shading obstructions. Which factor is most critical to optimize during the system design to meet these objectives?Planning and Estimating
  26. 176.A C-46 contractor is performing a site analysis for a ground-mounted PV system. The client's property has significant topographical variations, including a steep slope facing south. The contractor needs to determine the most cost-effective and structurally sound method for array installation while maximizing energy production. Which of the following approaches is most appropriate?Planning and Estimating
  27. 177.A C-46 contractor is performing a site analysis for a ground-mounted PV system on a property with varying soil conditions, including areas of loose sandy soil and compacted clay. To ensure the long-term stability and structural integrity of the array foundations, which of the following actions is most critical during the planning phase?Planning and Estimating
  28. 178.A C-46 contractor is designing a residential grid-tied PV system for a client whose annual electricity consumption is 12,000 kWh. The local utility has a net metering policy that credits excess generation at a 1:1 rate, but only up to 100% of the previous year's consumption. The contractor estimates the system's annual production will be 1,500 kWh per kWp of installed DC capacity. To achieve a 90% offset of the client's annual consumption, what is the ideal DC array size (in kWp)?Planning and Estimating
  29. 179.A C-46 contractor is conducting a site analysis for a ground-mounted PV system in a rural area. The client has expressed concerns about potential damage to the array from local wildlife and unauthorized access. Which of the following is the most effective measure to address these concerns during the planning phase?Planning and Estimating
  30. 180.A solar technician is working on a ground-mounted PV array where multiple parallel strings are connected to a combiner box. To safely de-energize the system for maintenance, the technician must follow a specific sequence. Which step is crucial immediately after opening the DC disconnects at the inverter but before working on the combiner box?Safety
  31. 181.A solar technician is working on a rooftop PV system and needs to identify the proper type of fire extinguisher for an electrical fire involving the inverter. Which class of fire extinguisher is specifically recommended for electrical fires?Safety
  32. 182.A solar crew is installing modules on a commercial building with a roof height of 25 feet. The roof has a low-slope (less than 4:12 pitch) and the work is being performed within 6 feet of the roof edge. Which of the following fall protection methods is required by Cal/OSHA?Safety
  33. 183.A C-46 contractor is performing a site analysis for a ground-mounted PV system on a large, undeveloped property. The client's primary concern is minimizing long-term operational and maintenance (O&M) costs. Which design consideration is most critical in achieving this goal?Planning and Estimating
  34. 184.A solar thermal installer is performing a system startup on a new closed-loop glycol system. After filling and purging air, the differential controller is turned on. The collector temperature is 160°F and the storage tank temperature is 90°F. The controller's ON differential is set to 15°F and the OFF differential is set to 5°F. What should the pump do, and why?Solar Thermal System Installation
  35. 185.A solar contractor is installing a new solar thermal system for domestic hot water. Which of the following is the maximum pressure relief valve (PRV) setting allowed for a potable water heater, as per the Uniform Plumbing Code (UPC)?Electrical and Plumbing Codes
  36. 186.A C-46 contractor is preparing an estimate for a residential PV system. The client is interested in maximizing their investment returns through energy arbitrage and participating in a virtual power plant (VPP) program. Which component is essential for meeting these specific client goals?Planning and Estimating
  37. 187.A solar thermal installer is commissioning a new closed-loop glycol system. During the initial fill, the installer notices that the pump is running but the flow rate is significantly lower than expected, and there are gurgling noises in the piping. What is the most probable cause of this issue?Solar Thermal System Installation
  38. 188.A solar thermal installer is troubleshooting a system where the collector fluid is getting excessively hot (stagnation temperatures) but the storage tank is not heating adequately. The circulating pump is confirmed to be running, and the differential controller is operating correctly. The installer also observes a significant pressure drop across the heat exchanger on the solar loop side. What is the most likely cause?Solar Thermal System Installation
  39. 189.A solar thermal installer is conducting a system startup and observes that the circulating pump frequently turns on and off in short bursts, even though the collector temperature is consistently 20°F higher than the tank temperature. The differential controller's ON setting is 12°F and its OFF setting is 4°F. What is the most likely cause of this 'short cycling' behavior?Solar Thermal System Installation
  40. 190.A solar installer is connecting a new grid-tied PV system to an existing residential service. The main service disconnect is rated for 200 A. The utility requires that the sum of the PV inverter output circuit overcurrent device and the main service overcurrent device does not exceed 120% of the service rating. If the PV system has an inverter output circuit breaker rated at 50 A, what is the maximum continuous current rating allowed for the main service overcurrent device, according to NEC 705.12(B)(2)(3)?Electrical and Plumbing Codes
  41. 191.A solar technician is working on a residential rooftop using an extension ladder to access the work area. The eave height is 18 feet. According to safety regulations, what is the minimum safe working length for the ladder to extend above the roof's bearing point?Safety
  42. 192.A solar installation crew is working on a new commercial building. During the panel installation, a worker accidentally drops a heavy tool from the roof onto the ground below, where other crew members are working. Which of the following safety measures was most likely insufficient or not properly implemented?Safety
  43. 193.A solar thermal installer is positioning a flat-plate collector array on a commercial building's flat roof. The array consists of three collectors in series. To ensure proper drainage and air venting, what minimum pitch should be maintained for the collector headers and piping?Solar Thermal System Installation
  44. 194.A solar technician is assigned to work on an existing PV system that includes a battery bank in a dedicated battery enclosure. During a routine inspection, the technician notices a strong, pungent odor resembling rotten eggs emanating from the battery enclosure. Which hazardous material is most likely being released?Safety
  45. 195.A C-46 contractor is preparing an estimate for a residential PV system. The client specifically requests a system that can provide backup power to critical loads during a grid outage, but also wants to maximize their self-consumption of solar energy to reduce utility bills. Which type of inverter configuration is best suited for these combined requirements?Planning and Estimating
  46. 196.A C-46 contractor is preparing an estimate for a residential PV system. The client expresses a strong preference for a low-profile, aesthetically pleasing installation that blends seamlessly with the roofline. Which mounting system characteristic is most important to meet this client's aesthetic requirement?Planning and Estimating
  47. 197.A solar thermal installer is performing the initial fill of a closed-loop propylene glycol system. To ensure adequate freeze protection for the expected winter temperatures of -10°F, what tool is essential for verifying the concentration of the glycol solution after mixing and filling?Solar Thermal System Installation
  48. 198.A homeowner reports that their closed-loop glycol solar thermal system is no longer providing adequate hot water, even on sunny days. The installer checks the system and finds the collector outlet temperature to be 180°F and the storage tank inlet temperature to be 100°F, while the pump is running normally. The glycol solution appears dark brown and smells burnt. What is the most likely cause of this performance degradation?Solar Thermal System Installation
  49. 199.A C-46 contractor is designing a grid-tied PV system for a residential client. The client has a limited budget but wants to ensure the system is as resilient as possible to minor grid fluctuations and momentary outages, without the full cost of a battery backup system. Which design choice offers a cost-effective compromise for this specific need?Planning and Estimating
  50. 200.A solar thermal installer is designing the piping for a drainback system where the collectors are located on the roof and the storage tank and drainback reservoir are in the basement. To ensure proper drainage of the collectors at night or during stagnation, what critical piping component must be included and properly sized?Solar Thermal System Installation