Free practice + study guide

CSLB Trade — Electrical (C-10)

CSLB Electrical (C-10) Trade Examination — Questions: Not published by CSLB · 210 minutes · Passing score: Not published by CSLB. CSLB's C-10 Electrical study guide, form 13E-10 (03/2026) gives these approximate section weights: Planning and Estimating 28%, Rough Wiring 27%, Finish Wiring and Trim 11%, Startup, Troubleshooting, and Maintenance 16%, Safety 18%. CSLB publishes section weights but no question count and no passing score for this exam. Last checked 2026-10-12. PrepPass also publishes a complete study guide for this exam as a downloadable book (239 pages, 240 practice questions inside, $14.99).

Your other CSLB exam

PrepPass Course: CSLB Law and Business

This license also needs the Law and Business exam (CSLB can waive an exam in some cases). 110 lessons, 732 practice questions.

Exam inside two weeks?

A printable colour cheat sheet for the exam: the format, the content areas and the figures it turns on, each checked against a named source and dated.

CSLB Class C-10 — Electrical cheat sheet PDF — $9.99 →

4 pages · US Letter · printable PDF · yours to keep

01

Test what you know · free, all of it

Five ways to practise.

The same 521 questions, dealt five ways. Pick the one that fits the time you have.

02

Learn what the questions test

Practice finds the gaps. Reading closes them. The six chapters below are free to read online. The study guide book is a separate download, sold on its own page.

Practice · free
521
questions, each explained — finds what you don't know yet
Learn · the guide
239
pages in the study guide book, section by section

The six sections, as chapters

free to read online
  1. 1Planning, Plans & EstimatingPlanning & EstimatingRead free →
  2. 2Services & DistributionRead free →
  3. 3Branch Circuits & Wiring MethodsBranch Circuits & WiringRead free →
  4. 4Equipment and SystemsEquipment & SystemsRead free →
  5. 5Testing and TroubleshootingTesting & TroubleshootingRead free →
  6. 6SafetyRead free →
Cover: CSLB Class C-10 Electrical — Trade Exam Study Guide (2026)
Study guide · PDF + EPUB
CSLB Class C-10 Electrical — Trade Exam Study Guide (2026)
239 pages · 240 practice questions inside · updated 2026-10-23
$14.99 one-time · yours to keep
03

Before you sit

Know the exam you're walking into.

04

See the questions first

Two from the bank, answered.

Real items, with the answer marked and the reason written out — the same format as all 521.

Branch Circuits & Wiring

In a dwelling living room, general-purpose receptacles must be placed so that no point measured horizontally along the floor line of any wall space is farther than what distance from a receptacle?

  1. A6 ftCorrect
  2. B10 ft
  3. C8 ft
  4. D12 ft

Why: Section 210.52(A) requires receptacles so no point along the wall line is more than 6 ft from an outlet, which effectively caps spacing at 12 ft. This lets any 6-ft appliance cord reach an outlet without an extension cord. 8, 10, and 12 ft each exceed the 6-ft reach the rule protects.2023 NEC §210.52(A)

Equipment & Systems

Using NEC Table 430.250, what is the full-load current (FLC) of a 10 HP, three-phase, 460-volt squirrel-cage motor?

  1. A11 A
  2. B14 ACorrect
  3. C21 A
  4. D28 A

Why: NEC Table 430.250 lists 14 A for a 10 HP 460 V three-phase motor; these table values (not nameplate amps) are used for conductor and overcurrent sizing. 28 A is the 230 V value, 21 A is a 15 HP motor, and 11 A is 7.5 HP at 460 V.2023 NEC Table 430.250

Read all 521 questions with answers →

06

The exam itself

CSLB Trade — Electrical (C-10), by the numbers.

QuestionsNot published by CSLBCSLB says only that “All trade examinations consist of multiple-choice questions.” No count appears in the study guide, the Examinations FAQ, or PSI's candidate bulletin.
Time210 minutesCSLB: “You will be given 3-1/2 hours to complete each examination.” It is per examination, not per sitting — a candidate taking Law and Business plus a trade exam gets 3-1/2 hours for each.
SectionsPlanning & Estimating · Services & Distribution · Branch Circuits & Wiring · Equipment & Systems · Testing & Troubleshooting · Safety
Passing scoreNot published by CSLBCSLB: “You will be informed at the test site about the percentage of correct answers needed to pass each examination,” and, in Get Licensed to Build Q14, that the percentage “varies for each exam”. Passing candidates are never shown their own score. PrepPass states no passing score for this exam.
Our bank521 questions · updated August 2026Written from California Contractors State License Board (CSLB)
LanguagesEnglish · 中文 · Español
SourceCalifornia Contractors State License Board (CSLB)Verified 2026-10-12

Full facts and sources →

07

Helpful resources

The board's own page, and what else helps.

Apply / register — CSLB (official) →

Recommended prep — books & tools

  • NFPA 70: National Electrical Code (NEC) 2023

    The exact code the C-10 electrical trade exam is written from.

    See it on Amazon →
  • Ugly's Electrical References

    Pocket-size formulas and tables to answer calculation questions fast.

    See it on Amazon →

This section contains affiliate links. As an Amazon Associate, PrepPass earns from qualifying purchases. We may earn a commission if you buy through these links, at no extra cost to you.

08

Contractor License Exams

On the same path.

09

Questions

Asked before starting.

Is the practice really free, or does it stop after a few questions?

All 521 questions, the timed mock and the report are free with no sign-up. A free account only adds saving your progress. The study guide book is sold separately, $14.99 one-time; nothing in the practice requires it.

Is your mock the same as the real CSLB Trade — Electrical (C-10)?

No. Ours is 100 questions in 210 minutes; the real exam is 210 minutes long. Use the mock for stamina and section timing, not as a score predictor.

What score do I need?

Not published by CSLB. CSLB: “You will be informed at the test site about the percentage of correct answers needed to pass each examination,” and, in Get Licensed to Build Q14, that the percentage “varies for each exam”. Passing candidates are never shown their own score. PrepPass states no passing score for this exam.

What is on the CSLB Trade — Electrical (C-10)?

CSLB's C-10 Electrical study guide, form 13E-10 (03/2026) gives these approximate section weights: Planning and Estimating 28%, Rough Wiring 27%, Finish Wiring and Trim 11%, Startup, Troubleshooting, and Maintenance 16%, Safety 18%. CSLB publishes section weights but no question count and no passing score for this exam. Last checked 2026-10-12.

Who administers the CSLB Electrical (C-10) Trade Examination?

Contractors State License Board (CSLB), California Department of Consumer Affairs — exam delivered by PSI Services LLC. CSLB's legal existence is set by Business and Professions Code § 7000.5. CSLB states it has contracted with PSI to administer its examinations.

How many questions are on the CSLB Electrical (C-10) Trade Examination?

Not published by CSLB. CSLB says only that “All trade examinations consist of multiple-choice questions.” No count appears in the study guide, the Examinations FAQ, or PSI's candidate bulletin.

How long is the CSLB Electrical (C-10) Trade Examination?

210 minutes. CSLB: “You will be given 3-1/2 hours to complete each examination.” It is per examination, not per sitting — a candidate taking Law and Business plus a trade exam gets 3-1/2 hours for each.

How much does the CSLB Electrical (C-10) Trade Examination cost?

$450 — Original application (exam or waiver, one classification) (CSLB, one-time); $51.43 — Examination registration (each registration, first attempt or retake) (PSI Services LLC, per attempt); $200 — Initial license fee (sole owner) (CSLB, one-time); $350 — Initial license fee (non-sole owner: partnership, corporation, LLC, joint venture) (CSLB, one-time); $20 — C-10 electrician-certification surcharge, added to the active license renewal fee (CSLB, per renewal). Two payees: application and license fees go to CSLB, the per-exam registration fee to PSI. CSLB's 2023 “Get Licensed to Build” PDF still names a $100 rescheduling fee; it appears neither on CSLB's current fee list nor in Business and Professions Code § 7137 as amended effective 1 January 2026, so it is not stated here. The application fee is charged once per original license application and covers both required exams.

What languages is the CSLB Electrical (C-10) Trade Examination offered in?

English. CSLB names ten exams that have Spanish versions and C-10 is not one of them, so the C-10 exam is English only. For other trade exams and languages CSLB may allow an approved translator as an accommodation. CSLB does publish a Spanish C-10 study guide — that is a study guide, not a Spanish exam.

Is the CSLB Trade — Electrical (C-10) study guide a PDF?

Yes. CSLB Class C-10 Electrical — Trade Exam Study Guide (2026) downloads as PDF + EPUB (239 pages, 240 practice questions inside), $14.99 one-time, and the files are yours to keep. The 521 practice questions on this page stay free without it. See the study guide →

Practice questions are AI-assisted study material written from California Contractors State License Board (CSLB) and reviewed by PrepPass — for practice only, not official exam questions. Bank updated August 2026. PrepPass is an independent study resource and is not affiliated with, endorsed by, or approved by California Contractors State License Board (CSLB). Always confirm current exam details with California Contractors State License Board (CSLB).
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