How to Pass the California C-10 Electrical Contractor Exam
Quick answer: Start with the current CSLB C-10 outline, put most study time into Planning and Estimating plus Rough Wiring, and use mixed review to expose calculation, code-lookup, troubleshooting, and safety gaps.
Current C-10 exam outline
Official outline used: current CSLB C-10 study guide, effective for examinations scheduled on or after June 1, 2024. CSLB describes the percentages as approximate.
| Official section | Approximate weight | What to review |
|---|---|---|
| Planning and Estimating | 28% | Systems, plans and specifications, calculations, code requirements, materials, and energy planning. |
| Rough Wiring | 27% | Layout, access, raceways, panels, conductors, equipment, grounding and bonding. |
| Finish Wiring and Trim | 11% | Devices, motors, equipment, labeling, trims and sealants. |
| Startup, Troubleshooting, and Maintenance | 16% | Testing, common problems, repair and replacement, and test equipment. |
| Safety | 18% | Lockout/tagout, PPE, tools, hazardous materials, and job-site hazards. |
A six-week C-10 study plan
Peerless suggestion—not a CSLB or PSI requirement: adjust this schedule to your baseline and available time. No schedule can guarantee a passing result.
- Week 1: Read the outline, take a mixed baseline set, begin an error log, and review plans, code lookup, and calculations.
- Week 2: Study rough-wiring layout, access, raceways, panels, conductors, grounding, and bonding.
- Week 3: Review finish devices, motors, equipment, labels, trims, and sealants.
- Week 4: Practice energizing, testing, fault isolation, repair decisions, and test-equipment selection.
- Week 5: Review lockout/tagout, PPE, tools, hazardous materials, and job-site hazards.
- Week 6: Complete timed mixed sets and direct final review from the error log.
Worked calculation: measured voltage-drop percentage
A 120-volt circuit measures 120 V at the source and 114 V at the load. Drop = 120 − 114 = 6 V. Percentage = 6 ÷ 120 × 100 = 5%. This arithmetic exercise does not state a design limit or replace the applicable code.
C-10 study resources
- Free C-10 practice test — start without signup; email and marketing-email consent are required to view results.
- C-10 study guide
- C-10 online practice exam
- C-10 study guide and practice-exam bundle
- C-10 and Law & Business bundle
- Official CSLB C-10 classification
Do not leave Law & Business until last
Applicants for an original California contractor license generally need the trade examination and Law & Business. Keep a separate study rotation and error log for the business exam.
California exam prep by region
These classifications are statewide. For regional scheduling guidance, see San Diego contractor exam prep, Bay Area contractor exam prep, or Sacramento contractor exam prep.
Frequently asked questions
Which C-10 sections carry the most weight?
Planning and Estimating is approximately 28% and Rough Wiring is approximately 27%.
Does energy production and storage form a separate section?
No. The current outline places those topics within planning, rough wiring, finish wiring, and startup and maintenance.
Can I begin the free practice test without creating an account?
You can start without signup. An email address and marketing-email consent are required to view the result.
Is Peerless affiliated with CSLB?
No. Peerless is an independent exam-preparation provider and is not affiliated with, endorsed by, or sponsored by CSLB.
Sources
Peerless Institute is independent and is not affiliated with, endorsed by, or sponsored by CSLB. Verify current exam requirements with CSLB.
