Electrician Exam Questions

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Total questions: 310
Topics: 20
Calculation exercises: 99
Scenarios and diagrams: 24

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Showing 20 of 310 matching questions.

Fill percentages
beginner
NEC 2017
conduit-fill-001
What is the maximum permitted fill, as a percentage of a conduit's interior cross-sectional area, when more than two conductors are installed?
- 40 percent
- 31 percent
- 53 percent
- 60 percent
Fill percentages
intermediate
NEC 2017
conduit-fill-002
A single conductor is installed in a conduit. What percentage of the conduit's cross-sectional area may it occupy?
- 53 percent
- 40 percent
- 31 percent
- 60 percent
Fill percentages
intermediate
NEC 2017
conduit-fill-003
Exactly two conductors are pulled into a raceway. The maximum fill is:
- 31 percent
- 40 percent
- 53 percent
- 35 percent
Nipples
intermediate
NEC 2017
conduit-fill-004
A conduit nipple not exceeding 24 inches in length is installed between two enclosures. To what percentage may it be filled?
- 60 percent
- 40 percent
- 53 percent
- 31 percent
Conductor area
beginner
NEC 2017
conduit-fill-005
Four 12 AWG THHN conductors are to be pulled into a raceway. What is their combined cross-sectional area in square inches?
Permitted fill area
intermediate
NEC 2017
conduit-fill-006
Half-inch electrical metallic tubing has a total interior area of 0.304 square inches. What area is available when more than two conductors are installed?
Maximum conductor count
advanced
NEC 2017
conduit-fill-007
How many 12 AWG THHN conductors may be installed in half-inch electrical metallic tubing?
Checking compliance
advanced
NEC 2017
conduit-fill-008
Nine 10 AWG THHN conductors, each 0.0211 square inches, are proposed for three-quarter-inch EMT, whose 40 percent fill area is 0.213 square inches. Is the installation compliant?
- Yes, because the conductors total about 0.190 square inches, which is under 0.213
- No, because the conductors total about 0.190 square inches, which exceeds 0.213
- No, because more than three conductors may never share a raceway
- Yes, but only if the conduit is treated as a nipple
What counts toward fill
intermediate
NEC 2017
conduit-fill-009
How is an equipment grounding conductor treated in a conduit fill calculation?
- It is included, using its actual dimensions whether it is insulated or bare
- It is excluded, because it normally carries no current
- It is included only if it is insulated
- It is counted as half of a current-carrying conductor
Minimum conduit size
advanced
NEC 2017
conduit-fill-010
Six 8 AWG THHN conductors must be installed in electrical metallic tubing. Their combined area is 0.2196 square inches. Three-quarter-inch EMT offers 0.213 square inches at 40 percent fill and 1-inch EMT offers 0.346 square inches. What is the minimum trade size in inches?
Insulation type and area
intermediate
NEC 2017
conduit-fill-011
Why can two conductors of the same AWG size occupy different amounts of space in a raceway?
- Because different insulation types have different wall thicknesses, so their overall diameters differ
- Because copper and aluminium conductors of the same AWG have different metal diameters
- Because stranded conductors are always exactly twice the area of solid ones
- Because the fill percentage changes with the insulation's temperature rating
Conductor area
intermediate
NEC 2017
conduit-fill-012
Calculate the total cross-sectional area occupied by three 4 AWG THWN-2 conductors.
Applying a percentage
beginner
electrical-calculations-001
A continuous load measures 44 amperes. What is 125 percent of that load?
Applying a percentage
beginner
electrical-calculations-002
What is 80 percent of a 100-ampere overcurrent device rating?
Three-phase current from kVA
intermediate
electrical-calculations-003
What line current corresponds to a 30-kilovolt-ampere three-phase load operating at 208 volts?
Single-phase current from kVA
beginner
electrical-calculations-004
A single-phase 10-kilovolt-ampere load is supplied at 240 volts. Find the current.
Unit conversion
beginner
electrical-calculations-005
A calculated service load comes to 12,000 volt-amperes. Express this in kilovolt-amperes.
The three-phase factor
beginner
electrical-calculations-006
Which value is used as the square root of 3 in three-phase calculations?
- 1.732
- 1.414
- 1.571
- 3.142
Percentage change
intermediate
electrical-calculations-007
A feeder's measured demand grows from 80 amperes to 100 amperes. By what percentage has the load increased?
Volt-amperes from volts and amperes
beginner
electrical-calculations-008
A 277-volt luminaire branch carries 16 amperes. What is the connected load in volt-amperes?

Questions by topic

Question count by topic
Topic	Questions	Practice page
Electrical Theory	20	Practise
Ohm's Law	18	Practise
Voltage, Current, Resistance and Power	12	In mixed practice
Series and Parallel Circuits	16	Practise
Electrical Calculations	14	Practise
Wire Sizing and Ampacity	20	Practise
Conduit Fill	12	Practise
Voltage Drop	14	Practise
Load Calculations	20	Practise
Grounding and Bonding	18	Practise
Overcurrent Protection	16	In mixed practice
Transformers	14	Practise
Motors and Motor Controls	18	Practise
Wiring Methods and Materials	14	In mixed practice
Electrical Safety	20	Practise
NEC Requirements	18	Practise
Electrical Diagrams and Symbols	12	Practise
Troubleshooting	12	In mixed practice
Electrical Installation Practices	10	In mixed practice
Electrical Equipment and Devices	12	In mixed practice

How these questions are sourced and checked

Every question carries a source reference, a difficulty level, a code edition where one applies, and a verification status — and only questions marked verified are published. That last point is enforced in code rather than by policy: the published bank is filtered on verification status, so an unverified draft cannot reach a user.

Electrical safety questions cite OSHA 29 CFR 1910 Subpart S by paragraph. These are federal regulations in the public domain, so the citation links straight to the governing text and you can read the rule yourself.

Code questions cite the 2017 National Electrical Code as published by Public.Resource.Org at the Internet Archive, which is the most recent edition available as a citable public document. No NEC table is reproduced here; where a question needs a table value, that single value appears in the question as supplied data.

Theory and calculation questions rest on physics and arithmetic, so many carry no external source — the question is self-verifying. What they do carry is a machine-checked answer: each numeric answer has an arithmetic expression that reproduces it from the question's own figures, and the validation script evaluates all of them on every build.

Exam format facts — question counts, time limits, pass marks, code editions — come from the licensing authorities' own published material, and where an authority does not publish a figure we say so instead of estimating it.

Which code edition these questions use

Code-specific questions here are written to the 2017 edition of the National Electrical Code, because that is the most recent edition published as a citable public document, through Public.Resource.Org's publication of standards incorporated by reference. Every such question is tagged with its edition and cites the article or table it comes from.

Your examination may use a different edition. Texas examinations have been referenced to the 2026 NEC since 1 September 2026, and the North Carolina Board publishes the 2020 NEC for its exams. Confirm the edition in your licensing authority's candidate bulletin, and verify any value you intend to rely on against that edition.

How much does the edition actually change?

Most of what is tested here has been stable across recent editions: ampacity, standard device ratings, conduit fill percentages, box fill allowances and motor full-load currents. Article numbering and specific requirements do change, and we do not claim otherwise. No NEC table is reproduced on this site; where a question needs a table value, that single value is supplied in the question itself.

Practise by topic

Reading explanations is useful; being tested is better. Each topic page drills you on it.

Questions about the question bank

Where do these electrician exam questions come from?

They are original, written from published sources. Electrical safety questions cite OSHA 29 CFR 1910 Subpart S, which is public-domain federal regulation. Code questions cite the 2017 National Electrical Code as published by Public.Resource.Org. Theory and calculation questions rest on physics and arithmetic that you can verify yourself. Exam format facts come from the licensing authorities' own bulletins.

Are these real exam questions?

No. Real examination items are confidential and copyrighted, and any site offering them is selling you something it should not have. These questions cover the same subject matter as the published content outlines, which is what actually prepares you.

How do I know the answers are right?

Three ways. Every question carries a source reference, and for code and safety questions a link to the source document so you can check it yourself. Every numeric answer carries an arithmetic expression that a validation script evaluates and compares against the answer key, failing the build on any disagreement. And the bank is checked for duplicate identifiers, near-duplicate wording, invalid options and missing references before it is published.

What is the difference between the question types?

There are four. Multiple-choice (187 questions) matches the exam format. Calculation exercises (99) require you to type a number, graded against a stated tolerance. Diagram exercises (12) ask you to read an original circuit or plan drawing. Troubleshooting scenarios (12) give you meter readings and ask for a diagnosis.

Can I practise without creating an account?

Yes, and there is no account to create. Progress is kept in your browser's local storage, so nothing leaves your device. Clearing your browser data, or switching browser or device, starts you fresh.

How many questions should I work through before sitting the exam?

A more useful target than a question count is an accuracy threshold. Work topic drills until you are consistently above 80 percent on each topic, then take timed exam simulations until your timed score is comfortably clear of the 70 percent pass mark. The per-topic breakdown after each exam tells you what to study next.