How Many Questions Are on the C-10 Exam?

The short answer

There are two exams standing between you and a California C-10 electrical contractor license, and they are different lengths:

That is 215 questions total across two separate appointments. You have to pass both. Passing one does not get you a license, and there is no partial credit for being strong on the trade side and weak on the business side.

Question counts and time limits are set by CSLB and can be revised. The numbers above reflect the current exam specifications, but your appointment confirmation is the authority for your specific test date, and cslb.ca.gov is where any change gets published first. Check it before you plan your pacing down to the second.

Closed book means closed book

Both exams are closed book. You do not bring a Code book, you do not bring notes, and you do not bring a phone. Some test centers provide an on-screen or basic calculator; the proctor will tell you what is allowed and what goes in the locker. This matters more than the question count does, because it changes how you have to study. You are not learning where to look things up. You are learning to recognize the answer.

Plan for that in advance so nothing on test day surprises you. Our walkthrough of what exam day actually looks like covers check-in, ID requirements, and the tutorial screen.

How the trade exam is weighted

CSLB publishes a content outline for the C-10 trade exam that splits the 100 questions across five areas. The weighting is not even, and that is the single most useful planning fact in this article:

Planning and estimating plus rough wiring is 55 percent of the exam by itself. That is where load calculations, service and feeder sizing, conductor ampacity, overcurrent protection, raceway and box fill, and wiring method selection live. If you are budgeting study hours, more than half of them belong in those two areas.

The other half still bites people. Safety at 18 percent is not a throwaway section, and troubleshooting questions ask you to reason about a circuit rather than recall a table value. Our breakdown of what is on the C-10 electrical exam goes section by section.

One important note on sources: the trade exam is written against the California Electrical Code, which is the 2025 edition and adopts the 2023 NEC with California amendments. When you study a table or a rule, make sure the material you are using is on that edition. Older prep material will teach you numbers that are no longer right.

How the question count shapes your pacing

Divide the questions into the time and you get your budget:

• Trade exam: 100 questions in about 210 minutes is roughly 2 minutes and 6 seconds per question.
• Law and Business: 115 questions in about 210 minutes is roughly 1 minute and 50 seconds per question.

Those averages are misleading in a useful way. Most questions are straight recall and take twenty to forty seconds. A three-phase load calculation or a voltage drop problem can eat five minutes. The average holds only if you bank time on the easy ones.

A pacing plan that works for most candidates:

1. First pass. Answer everything you know cold. Mark anything that needs paper and math and move on. Do not let question 12 cost you question 90.
2. Second pass. Come back for the calculation questions with whatever time you banked. You will usually have 60 to 80 minutes left for 15 to 25 flagged items, which is plenty.
3. Third pass. Answer every remaining blank, even if it is a guess. There is no penalty for a wrong answer, so a blank is strictly worse than a guess.
4. Checkpoint yourself. At the halfway mark on the clock you should be at or past the halfway mark on the questions. If you are not, start moving faster immediately rather than at the end.

The reason this works is that the exam does not care which questions you get right. Twenty-eight planning questions are worth exactly as much as twenty-eight safety questions. Spending eight minutes proving out one hard calculation while three easy questions go unanswered is the most common self-inflicted failure in the room.

Both exams, two results

You get a pass or fail notice at the test center when you finish. CSLB does not release your numeric score on a pass, and the passing standard, re-examination waiting periods, and re-take fees are all published by CSLB rather than by us, so confirm those at cslb.ca.gov before you make plans around them. Our overview of exam format and scoring explains how the results notice reads.

If you fail one and pass the other, only the failed exam is re-scheduled. That is worth knowing because it changes your strategy: many candidates take the Law and Business exam first, since the material is more finite and a pass there is one thing permanently off the list. Others go trade-first while their field knowledge is sharpest. There is no wrong order, and our comparison of the trade exam versus Law and Business lays out the tradeoff.

What the numbers actually mean for you

One hundred questions is not a lot of surface area for a trade this wide. It means the exam samples broadly rather than digging deep, and it means a handful of missed calculation questions can genuinely decide the outcome. It also means you cannot cram your way past a weak area, because at 27 or 28 questions a section, one weak section is enough to sink a marginal score.

If you want an honest read on the difficulty involved, our piece on how hard the C-10 exam really is is more useful than any pass-rate rumor you will hear on a job site.

The thing that moves the needle is not reading about the exam, it is sitting with a timer and 100 questions until two minutes per question feels like plenty instead of a countdown. Timed practice questions built on the same section weighting are what turn a person who knows the trade into a person who passes the test.