CSLB C-46 Solar (Trade Exam) Practice Test
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| Administering body | Contractors State License Board (CSLB), California Department of Consumer Affairs — exam delivered by PSI Services LLC |
|---|---|
| Questions | Not published by CSLB What we read and found nothing in: CSLB — Step 7: Studying for the Examination |
| Time limit | 210 minutes |
| Passing score | Not published by CSLB What we read and found nothing in: CSLB — Step 7: Studying for the Examination |
| Fees |
Source: CSLB — List of All CSLB Fees |
| Languages offered | English |
Frequently asked questions
How many CSLB Trade — Solar (C-46) practice questions are here?+
A full bank of original CSLB Trade — Solar (C-46) practice questions across the official content areas, weighted like the real exam, with explanations. Free, no signup.
What is the CSLB Trade — Solar (C-46) exam like?+
A multiple-choice exam, 210 minutes. Practice by topic here, then take the full timed mock exam to gauge readiness.
Are these the real exam questions?+
No. Every question is 100% original, written from public primary sources with explanations. We never copy real exam questions or paid prep material.
Can I study in Chinese or Spanish?+
PrepPass practice is in English, 中文 and Español. The official exam is in English — switch the question language to English any time to rehearse the exact terminology you'll see on test day.
Is there a study guide for the CSLB Trade — Solar (C-46)?+
Yes. PrepPass sells CSLB C-46 Solar Trade Exam Study Guide (2026), a PDF + EPUB download, $24.99 one-time; the practice on this page stays free without it. See the study guide →
Sample practice questions
A few real questions from this free bank, with full explanations. Use the practice tool above for the whole set.
- 1. Planning and Estimating
A homeowner's highest bill is in August, but the bills vary widely by month. What is the best starting figure for sizing a PV system?
- a.The average bill in dollars
- b.The kWh from the most recent bill
- c.The August kWh multiplied by twelve
- d.The total kWh over twelve months
Answer: d
Explanation: DOE advises reviewing electricity bills to find annual needs in kWh, checking every month because use changes through the year. Multiplying the peak month by twelve oversizes the system, and dollars do not measure energy.
Source: DOE, Planning a Home Solar Electric System
- 2. Planning and Estimating
What default total system loss does NREL's PVWatts Version 5 apply, and how is it combined?
- a.5 percent, applied to AC output only
- b.14 percent, from losses multiplied together
- c.14 percent, the simple sum of losses
- d.25 percent, the simple sum of losses
Answer: b
Explanation: PVWatts uses a default total loss of 14 percent and notes that the total is not the sum of the individual losses; it is found by multiplying the reductions for soiling, shading, mismatch, wiring and the rest.
Source: NREL PVWatts Version 5 Manual
- 3. Solar Panel and Collector Installation
What must be true of every roof penetration made for a PV installation, per San Diego County's checklist?
- a.It must be inspected by the roofer
- b.It must be at least 24 inches from a rafter
- c.It must be secure and weather-tight
- d.It must be sealed with silicone only
Answer: c
Explanation: San Diego County's checklist requires all roof penetrations to be secure and weather-tight. The method follows the approved plan and manufacturer details, not a single sealant type.
Source: County of San Diego PDS 081S (2025 codes)
- 4. Solar Panel and Collector Installation
Why does NREL say ground-mounted arrays usually need more cleaning than rooftop arrays?
- a.They face north
- b.They sit closer to dust and pollen
- c.They are cleaned only by rain
- d.They have no glass
Answer: b
Explanation: NREL notes that cleaning requirements increase for ground-mounted arrays because they are closer to the source of airborne dirt and pollen.
Source: NREL Best Practices for O&M of PV and ESS
- 5. PV System Installation and Commissioning
Where in a panelboard does San Diego County's checklist require the PV connection to be positioned?
- a.In the middle of the busbar
- b.Directly next to the main breaker
- c.Opposite the feeder or main
- d.On the neutral bar
Answer: c
Explanation: The checklist requires the PV connection in the panelboard to be positioned at the opposite (load) end from the input feeder or main circuit location, consistent with the 120 percent rule.
Source: County of San Diego PDS 081S (2025 codes)
- 6. PV System Installation and Commissioning
What can a grid-forming inverter do that a conventional grid-following inverter cannot?
- a.Operate without any DC source
- b.Ignore the utility's interconnection rules
- c.Restart a grid that went down
- d.Raise module efficiency above 40 percent
Answer: c
Explanation: DOE explains that grid-forming inverters can start up a grid if it goes down, a process called black start, while grid-following inverters need a signal from the grid to match.
Source: DOE, Solar Integration: Inverters and Grid Services Basics
- 7. Solar Thermal Installation
In a one-tank solar water heating system, where is the backup heater?
- a.On the roof beside the collector
- b.In a separate tank downstream
- c.There is no backup in one-tank systems
- d.In the same tank as solar storage
Answer: d
Explanation: DOE explains that in one-tank systems the backup heater is combined with the solar storage in one tank; in two-tank systems the solar tank preheats water for a conventional heater.
Source: DOE Energy Saver, Solar Water Heaters
- 8. Service, Operation, and Maintenance
NREL describes wire management failures on PV arrays. Which cause is named?
- a.Modules that face true south
- b.Plastic ties that break or pinch
- c.Conductors that are too large
- d.Inverters that are listed to UL 1741
Answer: b
Explanation: NREL notes that wire management depends on plastic ties and grommets that can break or pinch wires, and on exposure to sunlight, wind, ice and chewing rodents.
Source: NREL Best Practices for O&M of PV and ESS
- 9. Service, Operation, and Maintenance
A solar water heater in a dusty rural area delivers less heat each summer. What simple cause does DOE point to?
- a.Sunlight is weaker in rural areas
- b.Dusty or soiled collectors perform poorly
- c.The storage tank is too well insulated
- d.Glycol makes collectors too hot
Answer: b
Explanation: DOE notes that dusty or soiled collectors perform poorly and that periodic cleaning may be needed where rain does not rinse them, such as near plowing dust or birds.
Source: DOE Energy Saver, Solar Water Heating System Maintenance and Repair
- 10. Safety
A plywood cover will guard a roof opening during solar work. How strong must it be?
- a.No minimum, if it is marked
- b.At least 100 pounds per square foot
- c.400 lb or twice the load, whichever is greater
- d.Strong enough for one worker
Answer: c
Explanation: Section 1632 requires covers to safely support the greater of 400 pounds or twice the weight of employees, equipment and materials that may be imposed on any square foot, to be secured, and to be marked "Opening--Do Not Remove."
Source: Cal/OSHA Title 8 section 1632