Checked against primary sources 2026-09-05
A different agency, a different exam
California C-10 Electrical Contractor Exam: CSLB Rules
The C-10 is a contractor license from the Contractors State License Board, not a certification from DIR. It takes two exams, both closed book, both 3 hours 30 minutes, booked through PSI. Here's what CSLB publishes and what it doesn't.
Test yourself: thirty free questions, timed
On this page
Two agencies, two credentials
People mix these up constantly, so it's worth being blunt. The Department of Industrial Relations certifies individual electricians, through the Electrician Certification Unit inside its Division of Labor Standards Enforcement. The Contractors State License Board licenses the contracting business, and C-10 Electrical is its classification for electrical work.
A C-10 doesn't certify you as an electrician and a General Electrician certification doesn't license you to contract. If you want to run the work, you need the C-10. If you want to do the work for a C-10 holder, you need the certification. The contractor page covers the license side in full.
The two exams
CSLB says an applicant must take and pass two examinations as a condition of licensure: Law and Business, plus the trade exam for the classification. The one exception it names is the C-61 Limited Specialty classification, which isn't relevant to C-10.
You get 3 hours 30 minutes to complete each examination. Each carries its own fee, and the two can be scheduled on the same day or on different days.
CSLB doesn't publish a question count or a passing score for the C-10 trade exam on the examination FAQ we read, and the trade study guide's contents weren't reached this session. So we won't print a number we can't point at. If you need one, ask CSLB directly.
Closed book, and that word means what it says
This is the sharpest difference from the DIR certification exam. The C-10 exams are closed book. Reading materials and textbooks are prohibited items, and so are phones, calculators, notes and food.
The DIR exam hands you three references on screen. CSLB hands you nothing. If you're sitting both in the same year, don't carry a study habit from one into the other.
A valid government issued photo ID is required at the test center.
Booking, and where the centers are
Scheduling runs through PSI, online any hour of the day or by phone at (877) 392-6422. A cancellation less than 48 hours before the exam forfeits the appointment.
CSLB lists its California test center cities: Agoura Hills, Atascadero, Bakersfield, Carson, Diamond Bar, El Monte and Santa Fe Springs, Fresno, Irvine, Lawndale, Redding, Riverside, Sacramento, San Diego, San Francisco, Santa Clara, Santa Rosa, Union City, Ventura, Visalia and Walnut Creek. Outside California the trade exam is offered in Oregon only, at Wilsonville. The Law and Business exam travels further: CSLB's FAQ also offers it in Colorado, Connecticut, Georgia, Illinois, Iowa, Kansas, Massachusetts, Michigan, New Jersey, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Tennessee, Texas and Virginia.
That list is worth comparing with the DIR exam, where neither the bulletin nor the DIR page names any California city and you pick a site inside the Pearson VUE system instead.
What gets you to the exam
Four years of experience in the classification you're applying for. Credit is only given for experience at a journey level or as a foreman, supervising employee, contractor or owner-builder.
Education can substitute for up to three years: up to 1-1/2 years for an A.A. in building or construction management, up to two years for a four year degree in a field such as architecture or engineering, and up to three years for an apprenticeship certificate or a four year degree in construction technology or management. At least one year has to be practical experience.
Every experience claim has to be verified by a qualified and responsible person with firsthand knowledge, which CSLB lists as an employer, contractor, foreman or supervisor, fellow employee, other journeyman, union representative, building inspector, architect, engineer or homeowner.
Retakes and the 18 month clock
If you fail, you can retake after 21 calendar days. That's a much shorter wait than the 60 days on the DIR certification exam.
The outer limit is the one to watch: you have 18 months from acceptance of your application to pass. Miss that and you're starting the application over.
The money around it
The exam fees sit inside the application. CSLB's fee list prints an Original Application for one classification at $450, then an Initial License Fee of $200 for a sole owner or $350 for a non sole owner once you pass.
At issuance you also need a $25,000 Contractor Bond and a $25,000 Bond of Qualifying Individual, plus proof of Workers' Compensation Insurance, with an exemption available for most contractors who have no employees. CSLB lists an LLC employee or worker bond and LLC liability insurance as requirements too, without printing the amounts.
What CSLB publishes to study from
CSLB puts out two study guides, one for the C-10 Electrical trade exam and one for Law and Business, both linked from its examination study guides page.
Our practice questions are written on the National Electrical Code, which is the trade side of the C-10 paper rather than the law side. They're useful for the code arithmetic and useless for the law exam, and we'd rather say so. The practice hub explains what's in the sets.
Questions people ask
Is the California C-10 exam open book?
No. Both CSLB exams are closed book, and reading materials, textbooks, phones, calculators, notes and food are prohibited items. That's the opposite of the DIR certification exam, which supplies its references on screen.
How long is the C-10 exam?
You get 3 hours 30 minutes for each of the two examinations, Law and Business and the trade exam. They can be scheduled on the same day or on different days.
How many questions are on the C-10 trade exam?
CSLB's examination FAQ doesn't print a question count or a passing score, and we didn't reach the contents of the trade study guide, so we won't guess. Ask CSLB, or read the C-10 study guide it publishes.
How soon can I retake the C-10 exam?
After 21 calendar days from the failure. You have 18 months from acceptance of your application to pass, which is the deadline that actually catches people out.
How much experience do I need for a C-10?
Four years in the classification, credited only at journey level or as a foreman, supervising employee, contractor or owner-builder. Education can substitute for up to three years, and at least one year has to be practical experience.
Where can I sit the C-10 exam?
CSLB lists twenty California cities including Sacramento, San Francisco, Fresno, Riverside, San Diego and Santa Clara. Outside California the trade exam is offered in Oregon only, at Wilsonville, while the Law and Business exam is offered in eighteen states, Oregon among them. Scheduling is through PSI online or at (877) 392-6422.
Do I need the DIR certification before I can get a C-10?
They're separate credentials from separate agencies with separate requirements, and CSLB's applicant pages don't name the DIR certification as a condition of the C-10. Read both sets of rules rather than assuming one implies the other.
Thirty free questions, timed, with the working shown
Every miss comes back with the arithmetic worked out and the code section named, so you learn the trap and not just the answer. No account.
All questions here are original. They are not actual exam questions, and no question bank can promise you a pass.
What this page cites
- CSLB examination FAQ Gives the 3 hours 30 minutes per exam, the closed book rule, the prohibited items, PSI scheduling, the 21 day retake wait, the 18 month limit, the test center cities and the states outside California where each exam is offered. source
- CSLB applicants page States that an applicant must take and pass two examinations, Law and Business plus the trade exam. source
- CSLB experience requirements Sets four years of journey level or supervisory experience and the education substitutions up to three years. source
- CSLB C-10 classification detail Describes the scope of electrical contracting under Business and Professions Code sections 7008 and 7059. source
- CSLB fee schedule Prints the $450 original application for one classification and the initial license fees of $200 and $350. source
- CSLB examination study guides Links the C-10 Electrical and Law and Business study guides CSLB publishes. source
The 2023 to 2026 section crosswalk maps every section that moved, both directions, $29 once.