C-46 Solar exam questions, with answers
10 practice questions for the CSLB Solar trade exam, each with the answer, a plain explanation and the source it rests on.
These are not real exam questions. CSLB does not release its test questions or answer keys, and nobody else has them. We write our own questions from the C-46 outline and the codes, standards and references CSLB lists for the exam. Each answer names its source so you can check it.
The C-46 exam has 6 sections. The questions below are grouped by section, with the share of the exam each one carries. Read the question, pick an answer, then open “Show the answer”. The other questions of the free test, scored section by section, are in the free 25-question C-46 test.
Planning and Estimating · 14% of the exam
Evaluating client needs and site feasibility; designing and engineering systems; interpreting plans; estimating job costs.
1. Your company holds only a C-46 Solar license. A client who just signed for a rooftop PV system also asks you to build a wood patio cover in the back yard that has nothing to do with the solar work. Under 16 CCR 832.46, which building trade work may your company perform?
- Only the trade work required to install the solar energy system
- Any building trade work on a property where you hold a solar contract
- Any building trade work if the client signs a separate written contract
- Building trade work up to the value of the solar part of the contract
Show the answer
Answer: A. 16 CCR 832.46 says a solar contractor installs, modifies, maintains and repairs thermal and photovoltaic solar energy systems, and may not undertake or perform building or construction trades except when required to install such a system. A patio cover unrelated to the solar work is outside that scope however the contract is written or priced, so it needs a contractor licensed for that work.
Source: 16 CCR 832.46(a), CSLB Licensing Classifications: C-46 Solar Contractor (16 CCR 832.46)
Solar Panel/Collector Installation · 17% of the exam
Installing roof-mount collectors; installing ground-mount collectors; making weatherproof penetrations.
2. Exposed 6 AWG single-conductor PV wire runs from a rooftop combiner along the rails of the array. Under the 2025 California Electrical Code (NEC 2023) 690.31(C)(1), what is the longest interval at which this cable may be supported and secured?
- 12 in
- 24 in
- 36 in
- 54 in
Show the answer
Answer: D. 690.31(C)(1) requires exposed PV cables to be supported and secured at intervals not over 24 in when they are 8 AWG or smaller, and not over 54 in when they are larger than 8 AWG; 6 AWG is larger than 8 AWG. The 24-in limit is the one for smaller cables such as module leads, and 12 in is the support spacing for PV wire laid in an outdoor cable tray.
3. Your company is designing a multi-row tilted PV array for the flat roof of a public school, a Division of the State Architect (DSA) project under the 2025 California Building Code. The engineer wants to lower the wind loads on the inner rows because the outer rows shelter them, without a wind tunnel study or a SEAOC PV2 justification. Under DSA IR 16-8, what applies?
- Inner rows may take a 25 percent wind load reduction once the array has more than three rows
- Inner rows may use reduced wind loads, but attachments to the roof structure must use full loads
- No wind load reduction for row-to-row shielding may be taken for panels, frames or attachments
- Reduced wind loads may be used for panels and frames if the roof parapet is at least 3 ft high
Show the answer
Answer: C. DSA IR 16-8 section 3.1.3 says no reduction of wind load may be taken for the shielding or shadowing effect of multiple rows of solar panel arrays in the design of the panels, support frames and attachments to the roof framing or structure. DSA may consider shielding only as an alternate means of approval, when it is derived from an ASCE 7 Chapter 31 wind tunnel procedure or justified with SEAOC PV2 section 4.3.
Source: DSA IR 16-8 (2025 CBC), section 3.1.3 Shielding or Shadowing Effects on Rooftop Solar Panel Systems
Photovoltaic (PV) System Installation and Commissioning · 28% of the exam
Installing basic PV systems; installing energy storage systems (ESS); interfacing with the utility grid; installing standalone PV systems; labeling PV components; system testing, configuration and monitoring, and educating the client.
4. Under the 2025 California Energy Code, as summarized on the California Energy Commission's Solar PV and BESS page, which newly constructed building is prescriptively required to include a battery energy storage system (BESS)?
- A new duplex (two dwelling units) with a rooftop PV system
- A new nonresidential occupancy, such as an office
- A new single-family home with electrical service over 125 A
- A new single-family home whose PV system is over 4 kW dc
Show the answer
Answer: B. The CEC page says a BESS is prescriptively required for newly constructed nonresidential and high-rise multifamily buildings. New single-family homes (one or two dwelling units) that will not install a battery must instead meet the mandatory BESS-ready rules, which apply to homes with electrical service over 125 A; they get infrastructure for a future battery, not a battery.
5. During a utility outage, a homeowner asks why her grid-tied PV system, which has no battery, produces nothing even on a sunny day. Under the 2025 California Electrical Code (NEC 2023) 705.40, what must her listed interactive inverter do when utility power is lost?
- Stop exporting or disconnect, and stay off until all utility phases are restored
- Stop exporting for a few minutes, then restart to supply the house circuits alone
- Keep feeding the house loads, but stop exporting until the utility is restored
- Disconnect only the neutral, and reconnect as soon as one utility phase returns
Show the answer
Answer: A. 705.40 requires interactive equipment to disconnect automatically from all ungrounded conductors of the primary source when that source is lost, and not to reconnect until all phases are restored; a listed interactive inverter may instead automatically cease exporting power. A grid-tied inverter without a backup system therefore cannot keep running the house during an outage.
Solar Thermal Installation · 7% of the exam
Installing solar hot water systems; installing pool heating systems.
6. The cold water line to a new solar storage tank passes through a pressure reducing valve, so you add a thermal expansion tank on the cold supply downstream of that valve. According to DOE's job aid for installing a solar water heater, how do you set the expansion tank's air pressure?
- Equal to the incoming water pressure
- 10 psi above the incoming water pressure
- About half the incoming water pressure
- Equal to the tank's T&P valve setting
Show the answer
Answer: A. The DOE job aid says that where the cold-water supply passes through a check valve, pressure reducing valve or backflow preventer, an expansion tank goes on the cold line downstream of those valves, sized per the maker and code, supported rigidly, and set to a pressure that matches the incoming water pressure.
Source: DOE Job Aid: Install a Solar Water Heater, steps 11-13 (SWS 7.0302.6l, 7.0303.5d-e)
Service, Operation, and Maintenance · 15% of the exam
Evaluating PV systems; evaluating thermal systems; repairing and replacing components.
7. A commercial client wants an infrared (thermal camera) survey of her array while it keeps producing power. According to the IEA PVPS review of infrared and electroluminescence imaging (T13-10), which set lists the main thermal abnormalities such a survey finds?
- Hot cells, heated bypass diodes, heated string fuses and hot cable connections
- Heated bypass diodes, wrong grid settings, hot cells and mismatched module ratings
- Hot cells, low insulation resistance, reversed polarity and wrong grid settings
- Hot cable connections, inverter firmware faults, low string voltage and hot cells
Show the answer
Answer: A. The IEA PVPS review says modules can be checked with a thermal camera without interrupting operation, and it lists the main thermal abnormalities as hot cells (hot spots from broken glass, shading or cell problems), heated bypass diodes in the junction box, heated string fuses in combiner boxes, and heated dc and ac cables and connection points. Insulation resistance, polarity, firmware and grid settings are found with electrical tests and inverter checks, not with a thermal image.
Source: IEA PVPS T13-10:2018, 2.3 Classification and evaluation (main thermal abnormalities)
8. You must remove a client's PV array so the house can be re-roofed, then reinstall it. The roof already has two layers of asphalt shingles, and the roofer proposes a third layer over them to save money. Under the 2025 California Residential Code R908.4, is a roof recover allowed?
- Yes; a third layer is allowed if the roof framing is checked first
- Yes; a third layer is allowed if the new shingles are Class A rated
- No; a recover is allowed only on roofs with a slope of 4:12 or more
- No; a roof that already has two or more coverings must be torn off
Show the answer
Answer: D. R908.4 does not allow a recover when the existing roof is water-soaked or too deteriorated, when the covering is slate, clay, cement or asbestos-cement tile, or when the roof already has two or more applications of any roof covering. With two layers in place, the old roofing must be removed down to the deck before the new roof goes on and the array is reinstalled.
Source: CRC R908.4 (exceptions) and R908.3, 2025 California Residential Code (Title 24, Part 2.5)
Safety · 19% of the exam
Protecting the public from safety hazards; identifying and correcting unsafe working conditions; handling hazardous materials.
9. Your crew sets an extension ladder to reach the eave of a home, and its working length from the foot to the eave support is 20 ft. Under 8 CCR 3276(e), which the Construction Safety Orders (8 CCR 1675) apply to portable ladders used in construction, how should the ladder be set up?
- Foot about 4 ft out from the support; side rails at least 36 in above the eave
- Foot about 7 ft out from the support; side rails at least 12 in above the eave
- Foot about 5 ft out from the support; side rails at least 36 in above the eave
- Foot about 5 ft out from the support; side rails at least 24 in above the eave
Show the answer
Answer: C. 8 CCR 3276(e)(9) calls for a pitch where the horizontal distance from the top support to the foot is one-quarter of the working length, so 20 ft / 4 = 5 ft. 3276(e)(11) requires the side rails to extend at least 36 in above the upper landing; where that is not possible, the ladder must be secured at the top to a rigid support and a grab-rail provided.
Source: 8 CCR 3276(e)(9) angle of inclination; 3276(e)(11) access to landings; 1675(b)
10. An electrician wearing a metal watchband and a wedding ring will torque-check lugs within reach of exposed energized parts in an ac combiner panel. Under Cal/OSHA's 8 CCR 2320.7(d), what must the employer ensure?
- He keeps the ring and watch on if he wears rubber insulating gloves
- He removes the ring and watch, unless they do not add to the hazard
- He wraps the ring and watch in electrical tape before he starts work
- He keeps the ring and watch on if he works with only one hand inside
Show the answer
Answer: B. 8 CCR 2320.7(d) requires the employer to ensure that an employee working within reaching distance of exposed energized parts removes all exposed conductive articles, such as keychains, watch chains, rings, wrist watches or bands, unless they do not increase the hazards of contact with the energized parts. Taping them or working one-handed does not meet the rule.
Where to go from here
How the license works, from experience to fees: how to get a C-46 license. Everything about the course: the C-46 exam page.
Questions from our free C-46 test, written from CSLB License Examination Study Guide, Solar (C-46), form 13E-46 (03-2026), for examinations scheduled on or after July 1, 2023. CSLB notes that the percentages are approximate. Reviewed 14 October 2026. Study guidance only; we are not affiliated with CSLB or PSI.