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Question 1

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Per NEC 90.4, who has the authority to interpret code requirements and approve equipment and materials during a plan review?

The design engineer of record

The authority having jurisdiction (AHJ)

The licensed electrical contractor

The National Fire Protection Association

to track

2026 Statistics

Key Facts: ICC E3 Exam

70 Qs

Exam Questions

Open-book

3.5 hrs

Time Limit

3 min/question

Passing Score

Scaled score

$251-$319

Exam Fee

ICC member discount

2023 NEC

Reference Code

NFPA 70

50 States

Recognition

ICC certification

The ICC E3 exam has 70 multiple-choice questions with a 3.5-hour time limit in an open-book format. You must achieve a scaled score of 75 (approximately 75% correct, or 53 of 70 questions). The exam is based on the 2023 NEC (NFPA 70) and covers Articles 90 through 760. The exam fee runs roughly $251-$319 depending on ICC membership status. Testing is available at Pearson VUE centers or via ICC PRONTO remote proctoring 24/7.

Sample ICC E3 Practice Questions

Try these sample questions to test your ICC E3 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Per NEC 90.4, who has the authority to interpret code requirements and approve equipment and materials during a plan review?

A.The design engineer of record

B.The authority having jurisdiction (AHJ)

C.The licensed electrical contractor

D.The National Fire Protection Association

Explanation: NEC 90.4 establishes that the authority having jurisdiction (AHJ) is responsible for interpreting the code, approving equipment and materials, granting special permission, and waiving specific requirements when strict compliance is impractical. The plans examiner acts on behalf of the AHJ during document review. Exam tip: When a question asks 'who decides' on a code interpretation, the answer is almost always the AHJ.

2Which NEC article establishes the definitions used throughout the Code that a plans examiner must apply when reviewing submittal documents?

A.Article 90

B.Article 100

C.Article 110

D.Article 200

Explanation: NEC Article 100 contains the definitions that apply throughout the Code. Terms such as 'ampacity,' 'branch circuit,' 'feeder,' 'service,' and 'qualified person' are defined here and must be used consistently during plan review. Exam tip: When an unfamiliar term appears on the exam, check Article 100 first — the definition often resolves the question.

3For a one-family dwelling, NEC 230.79 requires the service disconnecting means to have a rating of not less than what value?

A.60 amperes

B.100 amperes

C.125 amperes

D.200 amperes

Explanation: NEC 230.79(C) requires the service disconnecting means for a one-family dwelling to have a rating of not less than 100 amperes, 3-wire. This minimum applies regardless of the calculated load. Exam tip: Even if the calculated load is only 80 amps, the minimum service for a one-family dwelling is still 100 A.

4Per NEC 230.71, the maximum number of service disconnects permitted for each service, each set of service-entrance conductors, or each service drop, permitted to be installed in a single enclosure is limited to how many?

A.Two

B.Four

C.Six

D.Unlimited

Explanation: Under the 2020 NEC, 230.71 allowed up to six disconnects grouped in a single enclosure or in separate enclosures. The 2023 NEC 230.71(B) now requires each service disconnect to be in a separate enclosure, with up to six disconnects permitted per service. Exam tip: Confirm which NEC edition your jurisdiction uses — the 2023 edition tightened this rule significantly.

5NEC 230.24(B) requires service-drop conductors passing over residential property and driveways to maintain a minimum vertical clearance of how many feet above final grade?

A.10 feet

B.12 feet

C.15 feet

D.18 feet

Explanation: NEC 230.24(B) requires service-drop and overhead service conductors to maintain a minimum 12-foot vertical clearance over residential property and driveways, and commercial areas not subject to truck traffic, for 120/240 V conductors. Exam tip: Memorize the clearance tiers: 10 ft at service entrance, 12 ft residential/driveways, 15 ft commercial, 18 ft over public streets subject to truck traffic.

6Per NEC 230.70(A)(1), the service disconnecting means must be installed at a readily accessible location either outside the building or inside nearest the point of entrance of service conductors. What is the specific distance requirement when installed inside?

A.Within a specific distance established by the AHJ

B.Within 3 feet of the point of entry

C.Within 5 feet of the point of entry

D.Within 10 feet of the point of entry

Explanation: NEC 230.70(A)(1) states the service disconnecting means shall be installed at a readily accessible location either outside a building or structure or inside nearest the point of entrance of the service conductors. The Code does not specify an exact distance — it is established by the AHJ. Exam tip: 'Nearest the point of entry' is an AHJ-interpreted requirement; many jurisdictions use 5 feet as a guideline but it is not codified.

7Per NEC 110.26(A)(1), the minimum depth of working space in front of electrical equipment operating at 277 V to ground with exposed live parts on one side and a grounded surface on the other side (Condition 2) is which of the following?

A.3 feet

B.3 feet 6 inches

C.4 feet

D.4 feet 6 inches

Explanation: NEC Table 110.26(A)(1) requires 3 ft 6 in of working clearance for equipment 151-600 V nominal to ground under Condition 2 (exposed live parts on one side, grounded parts on the other). Condition 1 is 3 ft, Condition 3 is 4 ft. Exam tip: Tab Table 110.26(A)(1) — working clearances are among the most frequently cited plans review items.

8A 400 A service feeds a commercial building. Using NEC 310.12 for dwellings or NEC 310.16 for commercial, what is the minimum size THWN copper service-entrance conductor required for the 400 A commercial service based on Table 310.16 at 75 C?

A.400 kcmil

B.500 kcmil

C.600 kcmil

D.750 kcmil

Explanation: Per NEC Table 310.16, a 500 kcmil THWN copper conductor has an ampacity of 380 A at 75 C, which is the next standard conductor size after 400 A (using 240.4(B), rounding up to 400 A OCPD) requires a 500 kcmil conductor. Actually 500 kcmil = 380 A; you need 600 kcmil for 400 A exact. Exam tip: For commercial services, always use Table 310.16 at the terminal temperature rating (usually 75 C), not the dwelling service conductor table.

9NEC 310.12 allows a reduced-size service or feeder conductor for a 120/240 V single-phase dwelling when the conductor serves as the main power feeder. This allowance permits the conductor ampacity to be what percentage of the service rating?

A.70%

B.75%

C.83%

D.90%

Explanation: NEC 310.12 permits service and feeder conductors in single-phase 120/240 V dwelling services and feeders to be sized at 83% of the service rating. For example, a 200 A dwelling service requires a conductor rated at least 200 x 0.83 = 166 A, which corresponds to a 2/0 AWG copper or 4/0 AWG aluminum. Exam tip: The 83% rule applies only to dwellings and feeders that serve the entire dwelling load — not subpanel feeders.

10Per NEC 250.24(C)(1), the grounded conductor (neutral) brought to the service disconnect must be sized not less than that specified in NEC Table 250.102(C)(1), and in no case smaller than what percentage of the largest ungrounded service conductor?

A.8.5%

B.12.5%

C.16.5%

D.25%

Explanation: NEC 250.24(C)(1) references Table 250.102(C)(1) for sizing the grounded service conductor and requires that it not be smaller than 12.5% of the area of the largest ungrounded service conductor where the ungrounded conductors exceed 1100 kcmil copper. This ensures sufficient capacity to carry unbalanced neutral and fault current. Exam tip: For smaller services, use the table directly; the 12.5% rule kicks in only for very large conductors.

About the ICC E3 Exam

The ICC Electrical Plans Examiner (E3) exam is administered by the International Code Council and certifies individuals to review electrical construction documents for compliance with the National Electrical Code (NFPA 70) before permits are issued. The open-book exam tests in-depth knowledge of services, feeders, branch circuits, load calculations, grounding/bonding, hazardous locations, special occupancies, special equipment, and emergency/standby systems. Plans examiners act on behalf of the authority having jurisdiction (AHJ) to catch code violations on paper before they become expensive field problems. ICC E3 certification is recognized in all 50 states and is a senior credential for building department plan review staff and third-party plan review consultants.

Questions

70 scored questions

Time Limit

3.5 hours

Passing Score

75 (scaled score)

Exam Fee

$251-$319 (ICC (Pearson VUE / PRONTO))

ICC E3 Exam Content Outline

General Administration

Authority having jurisdiction, NEC Article 100 definitions, scope, and the plans examiner role per NEC Article 90

26%

Services

Service conductor sizing, disconnects, clearances, grounding electrode system, and bonding per NEC Articles 230 and 250

19%

Branch Circuit and Feeder Requirements

Load calculations, feeder sizing, overcurrent protection, tap rules, and panelboard loading per NEC Articles 210, 215, 220, and 240

10%

Wiring Methods and Protection

Raceway fill, box fill, conductor derating, underground cover, and cable protection per NEC Articles 300-358

14%

Equipment for General Use

GFCI/AFCI, receptacle spacing, HVAC OCPD, motor FLC/conductor sizing, transformers, and appliance circuits per NEC Articles 404-460

15%

Special Occupancies

Hazardous locations, commercial garages, health care, mobile homes, RV parks, marinas, and aircraft hangars per NEC Articles 500-555

Special Equipment

Swimming pool bonding/GFCI, signs, fire pumps, information technology, and EV charging per NEC Articles 600-680

Special Systems

Emergency systems, legally required standby, fire alarm circuits, Class 2/3, GFPE, and arc-flash labeling per NEC Articles 700-760

How to Pass the ICC E3 Exam

What You Need to Know

Passing score: 75 (scaled score)
Exam length: 70 questions
Time limit: 3.5 hours
Exam fee: $251-$319

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

ICC E3 Study Tips from Top Performers

1Tab the 2023 NEC heavily around Article 230 (services), 220 (load calcs), 250 (grounding/bonding), 310.16 (ampacity table), Chapter 9 Tables 4 and 5 (conduit and conductor fill), and Annex C (conduit fill for same-size conductors) — these are hit multiple times on every E3 exam

2Master both load calculation methods in Article 220 — the standard method (220.40 through 220.61) and the optional method for dwellings (220.82). Know when demand factors apply to ranges (Table 220.55), dryers (Table 220.54), and neutrals (220.61)

3Memorize service disconnect rules cold — NEC 230.71 (max six disconnects, 2023 requires separate enclosures), 230.79 (100A minimum for one-family dwellings), and 230.24 clearances (10/12/15/18 ft tiers)

4Drill grounding electrode requirements from Article 250 — 250.52 electrode types, 250.53(A)(3) ground rod spacing (6 ft minimum), 250.66 grounding electrode conductor sizing, and 250.122 equipment grounding conductor sizing from Table 250.122

5Know hazardous location classifications from NEC 500.5 — Class I (gases/vapors), Class II (dust), Class III (fibers), and Division 1 vs Division 2. Commercial garages (Article 511), gas stations (Article 514), and aircraft hangars (Article 513) all have specific classified area diagrams you must recognize

Frequently Asked Questions

What score do I need to pass the ICC E3 exam?

The ICC E3 exam requires a scaled score of 75 to pass, which corresponds to approximately 75% of questions answered correctly — about 53 out of 70 questions. If you pass, you see 'PASS' on your results screen — no numerical score is shown for passing candidates. If you fail, you receive a diagnostic report showing your performance by content area so you know which domains to restudy. ICC uses scaled scoring set by the ICC Exam Development Committee to normalize difficulty across exam forms.

Is the ICC E3 exam open-book?

Yes, the ICC E3 exam is open-book. You may bring the 2023 NEC (NFPA 70) as your reference. You can tab, highlight, and annotate your codebook, but sticky notes and loose inserts are not permitted. With 3 minutes per question on average, time pressure is real but more forgiving than the 2-minute/question residential exams. Successful candidates pre-tab Article 230 (services), Article 220 (load calcs), Article 250 (grounding), and all the Article 500-series hazardous locations before test day.

How hard is the ICC E3 exam?

The ICC E3 is one of the harder ICC electrical exams because plans examiners must apply the full NEC, not just residential chapters. Services (26%) and Branch Circuit/Feeder Requirements (19%) together make up 45% of the exam and involve table lookups, load calculations, and multi-step problems. Special Occupancies (15%) and Equipment for General Use (14%) add another layer of complexity around hazardous locations and motor calculations. First-time pass rates are estimated at 50-60% and most candidates log 120-180 study hours before testing.

What codebook do I need for the ICC E3 exam?

The current ICC E3 exam is based on the 2023 NEC (NFPA 70). Some jurisdictions still test on the 2020 NEC — always confirm the code edition on the ICC exam bulletin before purchasing. You can buy the NEC from NFPA or the ICC store; most candidates use a tabbed hard copy. You do NOT need the IRC, IBC, or any other reference for the E3 — the exam is 100% NEC. Consider investing in a pre-tabbed NEC or a tab kit designed for plans examiners.

What jobs can I get with ICC E3 certification?

ICC E3 certification qualifies you for electrical plans examiner positions with city, county, and state building departments, as well as third-party plan review firms. Average salaries range from $65,000-$110,000 depending on location and experience. Many jurisdictions require ICC certification as a condition of employment or promotion. The E3 is often paired with the E2 (Commercial Electrical Inspector) or C3 (Combination Plans Examiner) credentials to unlock senior code official roles and Certified Building Official (CBO) eligibility.

How do I prepare for the ICC E3 exam?

Start by obtaining the 2023 NEC and reading Articles 90, 100, 110, 200, 210, 215, 220, 225, 230, 240, and 250 — these cover the bulk of the exam. Tab every table in Article 310 (ampacities), Chapter 9 (conduit fill), and Annex C. Practice the standard and optional load calculation methods until you can run a service calc in under 5 minutes. Complete timed 70-question mock exams with your codebook. Focus heavy study time on Services (26%) and Branch Circuit/Feeder Requirements (19%). Plan for 120-180 total study hours.