C-10 Exam Facts: Every Number, With the CSLB Source
Every number below comes from a CSLB page, and each row links to it. If CSLB does not publish a number, this page says so instead of guessing. CSLB changes fees and rules, so check the linked page before you pay anything.
Who can apply
| Fact | What CSLB says | Source |
|---|---|---|
| Age | at least 18 years old | Get Licensed to Build |
| Experience | four years of journey-level experience in the last 10 years | Get Licensed to Build |
| Application fee | $450 with each application | Get Licensed to Build |
| Time to pass | 18 months from the day CSLB accepts your application | Exam FAQ |
The exams
| Fact | What CSLB says | Source |
|---|---|---|
| How many | two computer-based exams: Law and Business, and the C-10 trade exam | Get Licensed to Build |
| Time | 3-1/2 hours for each exam | Exam FAQ |
| Format | multiple choice, with four choices per question | C-10 study guide |
| Books | closed book: no reference materials may be used | C-10 study guide |
| Calculator | a calculator will be provided | C-10 study guide |
| Guessing | there is no penalty for guessing | C-10 study guide |
| Passing score | varies for each exam; ask CSLB | Get Licensed to Build |
| Code edition | 2025 California Electrical Code | C-10 study guide |
| Where | PSI has 20 locations in California; trade exams are taken in California or Oregon | Exam FAQ |
| Cancel without losing the fee | your notice must arrive two days before the exam | Exam FAQ |
| Spanish | Law and Business has a Spanish version; C-10 does not, but an approved translator can read it to you | Exam FAQ |
What the C-10 trade exam covers
CSLB's study guide divides the C-10 exam into five sections. CSLB says the percentages are approximate.
| Section | Weight |
|---|---|
| Planning and Estimating | 28% |
| Rough Wiring | 27% |
| Finish Wiring and Trim | 11% |
| Startup, Troubleshooting, and Maintenance | 16% |
| Safety | 18% |
Planning and Estimating and Rough Wiring together are more than half the exam. That is where most of your study time belongs. Our guide to what is on the C-10 exam goes topic by topic.
On exam day and after
- Results: you get a printed report at the end of the exam. A passing report does not show your score. A failing report shows your score and how many questions you got right in each section.
- Questions: CSLB does not let you review the test questions or the answer key afterward.
- After you pass: the initial license fee is $200 for a sole owner or $350 for a non-sole owner (good for two years).
- Bond: you need a $25,000 contractor's bond or cashier's check for an active license.
- Also required: the asbestos open book exam, fingerprints for a criminal background check, and workers' compensation proof or an exemption.
When you need a license at all
CSLB says any construction project valued at $1,000 or more in labor and materials combined must be performed by a licensed contractor. If the work needs a permit, you need a license no matter the cost.
What this page will not tell you
- A pass rate. CSLB's guide says the percentage needed to pass varies for each exam, and you can ask CSLB. Any site that quotes a C-10 pass rate as official should name its CSLB source.
- A "CSLB-approved" school. CSLB says there are no schools or application preparation organizations that are affiliated with or agents of CSLB. That includes us.
Where to start
The fastest way to find your weak section is to answer real practice questions under time pressure. Take the free practice test: it scores you by section, so you know which of the five sections to study first. Every one of our 1,202 practice questions is written to the 2025 California Electrical Code and the 2026 CSLB law book, in English and Spanish.