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Idaho Journeyman Electrician Exam — Practice Test & Study Guide

What This Practice Exam Covers

The Idaho Journeyman Electrician Exam consists of 100 questions answered in 270 minutes, with a passing score of 75% (75 correct answers). The exam is administered by a national testing provider and draws from seven topic areas that span NEC code knowledge, calculation skills, and applied installation requirements.

This practice exam is available in two formats. The free practice exam gives you 10 questions per attempt, pulled from a limited question pool. You can retake it as many times as you want — it's a solid way to gauge the question style and format before committing to full prep.

The full practice exam mirrors the real exam exactly: 100 questions, a 270-minute time limit, and questions drawn from a pool of 473+ items so every attempt generates a unique exam. No two attempts are identical, which means repeated sessions genuinely test your retention rather than your memory of a fixed question set. Questions are built from the same topic blueprint the official test provider uses.

What You'll Be Tested On

General Electrical Knowledge — 13 questions

This section opens with Ohm's Law calculations (voltage, current, resistance, and power), and examiners expect you to apply all four formula variations without prompting. Series circuit rules also appear here — specifically, how total resistance, current, and voltage drops behave in a series configuration. You will also need to know NEC scope: what installations Article 90.2(A) covers and what Article 90.2(D) excludes. Expect questions on how the NEC is organized (Article 90.3), how to distinguish mandatory language from permissive and explanatory language (NEC 90.5(A), NEC 90.5(B), NEC 90.5(C)), and how to read conductor color coding across 120/240-volt single-phase and 120/208-volt three-phase distribution systems (NEC 110.15).

Wiring and Protection — 25 questions

The heaviest topic on the exam. Conductor ampacity from NEC Table 310.16 is tested directly, including temperature correction and adjustment factors from NEC 310.15(C)(1). Service entrance requirements are heavily represented: minimum service conductor sizes (NEC 230.23(B), NEC 230.31(B)), clearance requirements (NEC 230.24(B)), underground service conductor requirements (NEC 230.30(A)), and the 100-ampere minimum rating for one-family dwelling disconnecting means (NEC 230.79(C)). Grounding electrode systems, overcurrent protection for service conductors, and physical protection of cables through structural members (NEC 300.4(A)(1), NEC 300.4(A)(2)) round out this section. With 25 items, this single topic accounts for one-quarter of your entire exam score.

Wiring Methods and Materials — 19 questions

Box fill calculations are a consistent point-earner here. You must be able to apply NEC Table 314.16(A) for standard box volumes and NEC Table 314.16(B)(1) to count conductor equivalents for devices, clamps, and equipment grounding conductors (NEC 314.16(B)(1), NEC 314.16(B)(4)). Questions also cover round box restrictions (NEC 314.2), conduit body requirements (NEC 314.3), pull box sizing for straight and angle pulls (NEC 314.28(A)(1), NEC 314.28(A)(2)), and box support methods (NEC 314.23(E)). Wiring in ducts, plenums, and air-handling spaces is tested, as is minimum cover depth for underground installations from NEC Table 300.5(A).

Equipment for General Use — 19 questions

This section covers luminaires, switches, receptacles, and flexible cords. Expect questions on wet and damp location luminaire requirements (NEC 410.10(A), NEC 410.10(D)), switch installation restrictions including the prohibition on switches inside tub or shower spaces (NEC 404.4(C)), and receptacle grounding and replacement rules (NEC 406.3(B), NEC 406.3(C), NEC 406.4(D)(6)). Fixture wire ampacity limits come from NEC 402.5 and NEC Table 402.5. Prohibited uses of flexible cords are tested against NEC 400.12, and flexible cord ampacity is drawn from NEC Table 400.5(A)(1).

Special Occupancies — 12 questions

Hazardous location classification (Class I, II, III and Division 1 and 2) is tested here and again in Special Conditions, so this material rewards double study time. Know the area classification rules for commercial garages (NEC 511.3, Article 511.3(C), NEC Table 511.3(C)) and motor fuel dispensing facilities (NEC Table 514.3(B)(1), Article 514.11(A)). Health care facility essential electrical systems require knowledge of Type 1 and Type 2 EES branch requirements (NEC 517.29(A), NEC 517.29(B)), patient care space receptacle and grounding rules (NEC 517.18(B)(1), NEC 517.19(C)(1)), and isolated ground receptacle requirements (NEC 517.16(A)). Swimming pool bonding, GFCI protection, and luminaire placement distances complete the section.

Special Equipment — 6 questions

Cranes, hoists, elevators, generators, and electric signs. Know conductor sizing for cranes and hoists (Article 610.14(C)), disconnecting means requirements (Article 610.21(D)), and overload protection (Article 610.33). For generators, generator conductor sizing (Article 445.13(A)) and overcurrent protection (NEC 445.6) are tested. Electric sign branch circuits and grounding fall under NEC 600.5(A) and NEC 600.3.

Special Conditions — 6 questions

Solar PV topics dominate here. Know maximum system voltage rules (Article 690.7), rapid shutdown requirements (Article 690.12(B)), arc-fault protection (NEC 690.11), and PV wiring method requirements (Article 690.31(G)). Hazardous location protection techniques — explosionproof, dust-ignitionproof, intrinsically safe, and purged/pressurized equipment — also appear (Article 500.7(B), Article 501.15(A)(1)).

Worked Sample Questions

Question 1 — Wiring and Protection
True or False: Service-entrance conductors for one-family dwellings must have a minimum rating of 200 amperes.

Correct Answer: FALSE
This is a classic trap. Per NEC 230.79(C), the service disconnecting means for a one-family dwelling must be rated at not less than 100 amperes, 3-wire. The 200-ampere figure is standard in new residential construction but is not the Code minimum. Candidates who confuse common practice with the actual code requirement consistently miss this question.

Question 2 — Wiring Methods and Materials
True or False: Round boxes are permitted to be used where conduits requiring locknuts or bushings are connected to the side of the box.

Correct Answer: FALSE
NEC 314.2 is direct on this point: round boxes shall not be used where conduits or connectors requiring the use of locknuts or bushings are to be connected to the side of the box. Round boxes are suitable for luminaire or device outlets fed by cable, not for conduit connections at the box wall.

Question 3 — Equipment for General Use
What type of switch is prohibited from being installed within tub or shower spaces?

• A. GFCI switches
• B. All switches unless part of a listed tub or shower assembly
• C. Timer switches only
• D. Dimmer switches only

Correct Answer: B
NEC 404.4(C) prohibits all switches within tub or shower spaces unless they are installed as part of a listed tub or shower assembly. The exception is narrow — the assembly itself must be listed. Choosing A, C, or D implies that only certain switch types are restricted, which is incorrect. The rule is categorical.

How to Read Your Score

The passing threshold is 75% — 75 out of 100 questions answered correctly. On your first practice attempt, treat your score as a diagnostic baseline, not a verdict on your readiness.

A score in the 50s or 60s is normal on a first attempt and tells you where the gaps are, not that you cannot pass. Use the topic-by-topic breakdown after each attempt. If you scored 60% on Wiring and Protection but 90% on General Electrical Knowledge, you know exactly where your study time should go — and Wiring and Protection carries 25 exam items, so improving there has the largest impact on your final score.

Scoring 70–74% on practice should not be taken as near-passing. Real exam conditions add time pressure and unfamiliar phrasing. A consistent practice score of 80% or higher across multiple attempts is a more reliable indicator that you're ready to sit. Each full practice attempt draws from 473+ questions, so retaking the exam tests genuine understanding rather than answer memorization.

Where Candidates Lose Points

Confusing mandatory and permissive language. The NEC uses "shall" for mandatory rules, "shall be permitted" for permissive rules, and "fine print" language for informational notes (NEC 90.5(A), NEC 90.5(B), NEC 90.5(C)). Exam questions deliberately test whether you know the difference.

Wrong ampacity table or missed correction factor. Pulling a number directly from NEC Table 310.16 without applying the temperature correction factor from NEC 310.15(C)(1) is one of the most common calculation errors on this exam. Always check whether a correction or adjustment applies before writing down your answer.

Box fill miscounts. Candidates often forget that a single equipment grounding conductor counts as one conductor regardless of how many are present, per NEC 314.16(B)(4), while each ungrounded and grounded conductor counts individually under NEC 314.16(B)(1). A one-count error changes the answer.

Hazardous location classification misapplication. Class I, II, and III locations with Division 1 and Division 2 distinctions appear in both Special Occupancies and Special Conditions. Confusing the division definitions — or mixing up commercial garage zone classifications under Article 511.3 with motor fuel dispensing rules under NEC Table 514.3(B)(1) — costs candidates on both topic sections.

Running out of time on the heavy sections. With 270 minutes for 100 questions, you have an average of 2.7 minutes per question. Calculation-heavy questions in Wiring and Protection and Wiring Methods and Materials can run long. Candidates who slow down on service entrance calculations and box fill early often rush through Special Occupancies at the end.

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