CSLB C-46 Solar Exam Guide (2026): Fees, Format, Sections and Study Plan
Legal Review by Tymon Berger, Construction Attorney, PNW Construction Law ·
The CSLB C-46 Solar exam is the California Contractors State License Board trade exam for solar contractors, covering photovoltaic, energy storage and solar thermal work under the California Electrical, Plumbing and Building Codes. This guide covers cost, format, pass score, open-book rules, retakes, experience, difficulty, how California differs and a study plan, sourced only from CSLB, DOE, Cal/OSHA and OSHA documents.
What Is the CSLB C-46 Solar Contractor License?
The C-46 is California's specialty contractor class for solar systems. It is issued by the Contractors State License Board (CSLB). Unlike a pure electrical license, the C-46 exam spans both sides of solar: photovoltaic (PV) systems that make electricity, and solar thermal systems that heat water and pools. The person who qualifies the license must pass two CSLB exams, the Law and Business exam and the C-46 trade exam.
CSLB's C-46 Solar study guide is the official outline. It applies to exams scheduled on or after July 1, 2023. If your work is mostly general electrical, compare it with our CSLB C-10 Electrical Exam Guide (2026): Fees, Format, Sections and Study Plan.
CSLB C-46 Exam Format at a Glance
| Item | CSLB C-46 rule |
|---|---|
| Question type | Multiple choice, four choices, one BEST answer |
| Open book | No. Closed book |
| Calculator | Provided; some questions need math |
| Guessing penalty | None |
| Passing score | Given to you at the test site |
| Vendor and retakes | PSI; 21-day wait; 18-month window |
CSLB does not state a question count or time limit in the C-46 study guide, only that "plenty of time is provided." We do not guess at those numbers. Our full mock exam uses its own practice length and says so.
The Six C-46 Sections and Their Weights
| Section | Weight | What CSLB lists |
|---|---|---|
| 1. Planning and Estimating | 14% | Client needs and site feasibility, design and engineering, plan reading, job cost estimates |
| 2. Solar Panel/Collector Installation | 17% | Roof-mount and ground-mount collectors, weatherproof penetrations |
| 3. PV System Installation and Commissioning | 28% | Basic and standalone PV, energy storage systems, utility interconnection, labeling, testing, monitoring and client education |
| 4. Solar Thermal Installation | 7% | Hot water and pool heating systems |
| 5. Service, Operation, and Maintenance | 15% | Evaluating PV and thermal systems, repairing and replacing components |
| 6. Safety | 19% | Protecting the public, correcting unsafe conditions, handling hazardous materials |
PV installation and commissioning is the largest section at 28%, and Safety is second at 19%. Together with collector installation they make up 64% of the exam, so hands-on install knowledge is the core. Solar thermal is only 7%, but PV-only installers often skip it entirely, and those are easy points to lose.
CSLB C-46 Sample Questions Explained
- PV power: a source circuit at 346 V DC and 8 A produces P = V × I = 2,768 W, or about 2.77 kW.
- Temperature effect: as module temperature rises, voltage decreases.
- Pool volume: 20 ft × 30 ft × 8 ft = 4,800 cubic feet. The guide's answer is 35,904 gallons (about 7.48 gallons per cubic foot). The trap answers use the right number in the wrong unit.
The samples show the C-46 mix: electrical math, PV physics, and plumbing-style volume calculations for thermal work. Practice unit conversions until they are automatic.
CSLB C-46 Cost: Application, License and Renewal Fees
From the CSLB list of all fees:
| Fee | Amount |
|---|---|
| Original application (one classification) | $450 |
| Initial license fee, sole owner / non-sole owner | $200 / $350 |
| Fingerprint processing (DOJ + FBI) | $32 + $17 |
| Active timely renewal, sole owner / non-sole owner | $450 / $700 |
| Additional classification on an existing license | $230 |
Unlike C-10 contractors, who pay a $20 renewal surcharge, the C-46 renews at the standard rates. The original license application adds that exam fees are paid directly to the testing vendor, the initial license fee is sent after you pass, and a $25,000 contractor's bond is required.
C-46 Experience Requirements
CSLB requires at least four years of experience in the classification within the last 10 years. Per CSLB's qualifying experience page, it must be at journey level or as a foreman, supervising employee, contractor or owner-builder, and a qualified person must verify it. Time as a helper, laborer or apprentice does not count. Owner-builder experience only qualifies for the B-General Building class.
Pass Score and Retakes
CSLB's Studying for the Examination page says you learn the required percentage at the test site, so no fixed official C-46 pass mark exists to quote. After approval, you have 18 months to pass. You may retest as often as needed within the retesting guidelines, waiting 21 days between attempts and paying the vendor each time through your PSI account.
How Hard Is the CSLB C-46 Solar Exam?
CSLB does not publish pass rates on the pages we checked. The study guide still points to the main challenges:
- Two trades in one exam. You need PV electrical knowledge and solar thermal plumbing knowledge. The guide lists both the California Electrical Code and the California Plumbing and Mechanical Codes, plus IAPMO's Uniform Solar, Hydronics and Geothermal Code.
- Closed book. No references, so rules and formulas must be memorized.
- Storage and grid. Energy storage systems, utility interconnection and standalone systems are all in the largest section.
- Math. Power, temperature effects, volumes and job costs come up, and you get a calculator for them.
Solar Safety Rules Worth Knowing Word for Word
Safety is 19% of the exam, and the study guide lists the Cal/OSHA safety orders as a reference. Key free rules:
- 29 CFR 1926.502: guardrail, safety net and personal fall arrest criteria, including anchorages for fall arrest that support at least 5,000 pounds per employee attached.
- 29 CFR 1926.1053: ladder rules, such as side rails extending at least 3 feet above the upper landing.
- Cal/OSHA §2320.2: energized work needs a supervision decision, training and suitable PPE, with approved insulated gloves above 250 volts to ground.
- Cal/OSHA §2320.4: lock the disconnect open, tag it, and block or dissipate stored energy, which matters with batteries and capacitors in ESS work.
For PV physics, the U.S. DOE solar photovoltaic technology basics pages explain cells, modules and arrays in plain language.
How California Differs From Other States
California gives solar its own contractor class. The C-46 lets a contractor install both PV and solar thermal systems, and the qualifier takes the same Law and Business exam as every other CSLB class. Other states set their own solar and electrical licensing rules, so check with their boards directly. National credentials such as the NABCEP PV Associate Exam Guide (2026): PVA Fees, Format, Domains and Study Plan are certifications, not California licenses.
Five-Week CSLB C-46 Study Plan
- Week 1, baseline: read the C-46 study guide and take 25 questions in our CSLB C-46 Solar Practice Test.
- Week 2, PV installation and commissioning (28%): string sizing, temperature effects, ESS, interconnection, labeling and testing.
- Week 3, collectors and thermal (24%): roof and ground mounts, flashing and penetrations, hot water and pool heating volume and sizing math.
- Week 4, safety and service (34%): fall protection, ladders, lockout, energized work rules, and troubleshooting PV and thermal systems.
- Week 5, planning and review: site feasibility and job cost estimates, then the CSLB C-46 Full Mock Exam closed book. Study the CSLB Law and Business Exam Guide alongside.
Frequently Asked Questions
How much does a CSLB C-46 Solar license cost?
The CSLB application fee is $450 for one classification. After you pass, the initial license fee is $200 for a sole owner or $350 for a non-sole owner. Exam fees go separately to the testing vendor, PSI.
Is the CSLB C-46 Solar exam open book?
No. The C-46 study guide says it is closed book and no reference materials may be used. CSLB provides a calculator.
What sections are on the C-46 exam?
Six: Planning and Estimating (14%), Solar Panel/Collector Installation (17%), PV System Installation and Commissioning (28%), Solar Thermal Installation (7%), Service, Operation, and Maintenance (15%) and Safety (19%).
What score do you need to pass the C-46 exam?
CSLB does not print a pass mark in the study guide. It says candidates are told at the test site what percentage of correct answers is needed.
How many times can I retake the C-46 exam?
As many times as needed within retesting guidelines during the 18 months after your application is approved, with a 21-day wait between attempts.
What experience do I need for a C-46 license?
At least four years of journey-level, foreman, supervisor or contractor experience in solar work within the last 10 years, verified by a qualified person.
Does the C-46 exam cover solar water heating?
Yes. Solar Thermal Installation is about 7% of the exam and covers hot water and pool heating systems.
Do I need the Law and Business exam too?
Yes. The qualifier must pass the CSLB Law and Business exam as well as the C-46 trade exam, unless a waiver applies.
TradeExamHub is independent and not affiliated with CSLB, PSI, DOE or Cal/OSHA. Our questions quote public CSLB, DOE, Cal/OSHA and eCFR text and do not come from any actual CSLB exam.