Idaho Master Electrician Exam

Idaho Master Electrician Exam: Complete 2026 Study Guide

Passing the Idaho Master Electrician Exam is one of the most significant milestones in an electrician's career. It proves you have the knowledge to oversee electrical work, pull permits, and run your own jobs — responsibilities that come with real accountability. The exam is challenging, but with the right preparation, it's absolutely passable. This guide covers everything you need to know: exam format, topic breakdown, sample questions, study materials, and practical tips to help you walk in confident on test day. Start by taking our free practice exam to see where you stand right now.

Idaho Master Electrician Exam Overview

Here's the fast-facts version of what you're dealing with:

• Total scored questions: 100
• Time limit: 270 minutes (4.5 hours)
• Passing score: 75% — meaning you need 75 correct answers out of 100
• Format: Multiple-choice, open-book (NEC and other approved references)
• Administered by: PSI Exams — check the official exam bulletin for scheduling and location details

The open-book format is both a blessing and a trap. Yes, you can reference your NEC during the exam. But if you're not already familiar with the code's structure, flipping pages looking for answers will burn through your 270 minutes fast. The goal of your study time isn't just to memorize rules — it's to internalize the code well enough to find answers quickly when you need them.

Topics Covered on the Idaho Master Electrician Exam

The exam tests eight topic areas. Here's how they break down by number of items, from heaviest to lightest:

Wiring and Protection — 25 Items

The single largest section. Expect questions on conductor ampacity tables, correction and adjustment factors, grounding and bonding (Article 250), overcurrent protection (Article 240), underground wiring minimum cover depths (Article 300.5), and physical protection through structural members (Article 300.4). This section rewards candidates who know Article 250 cold.

Wiring Methods and Materials — 20 Items

Closely related to Wiring and Protection but focused on box fill calculations (Article 314.16), conductor temperature ratings, securing and supporting boxes and enclosures (Article 314.23), and more on underground installations and cable protection. Be prepared to do math.

Equipment for General Use — 20 Items

Covers the everyday equipment you work with: receptacles (Article 406), luminaires in wet and damp locations (Article 410), switches (Article 404), flexible cords (Article 400), and fixture wire limitations (Article 402). This section tends to have practical, scenario-based questions.

Special Occupancies — 11 Items

Hazardous location classification (Class I, II, and III; Division 1 and 2), wiring in commercial garages and fuel dispensing facilities, health care facility essential electrical systems, and patient care space requirements. Broad topic, so prioritize the hazardous location rules and health care facility basics.

General Electrical Knowledge — 10 Items

Ohm's Law, series circuit calculations, NEC scope, code chapter organization, and understanding mandatory versus permissive language. Foundational material — don't overlook it just because it's weighted lighter.

Special Equipment — 6 Items

Cranes, hoists, elevators, escalators, and generators. Covers wiring methods, disconnecting means, overcurrent protection, and generator installation requirements (Article 445 and Article 620).

Special Conditions — 5 Items

Hazardous location protection techniques, solar PV system requirements (maximum voltage, overcurrent protection, arc-fault protection), rapid shutdown, and health care facility branch requirements.

Communication Systems — 3 Items

Cable types by location (plenum, riser, general-purpose), grounding and bonding of communications cables, separation from power conductors, primary protector requirements, and aerial wiring clearances.

Sample Idaho Master Electrician Exam Questions

Here are five questions representative of what you'll see on the real exam. Work through them on your own — the answers are not provided here. Take our free practice exam to check your reasoning and get detailed feedback.

Question 1 — Wiring and Protection

You are designing the grounding electrode system for a new commercial building. A single ground rod is driven but you have not tested its resistance to earth. What is the Code requirement regarding this installation?

• A) A single ground rod is sufficient without any additional electrode.
• B) Two ground rods are always required regardless of measured resistance.
• C) The ground rod must achieve a resistance of 10 ohms or less, or a supplemental electrode is required.
• D) The ground rod must be supplemented by an additional electrode unless its resistance to earth is 25 ohms or less.

What this tests: Your knowledge of Article 250's grounding electrode requirements — specifically the rules around supplemental electrodes when resistance hasn't been verified.

Question 2 — Equipment for General Use

You are a master electrician planning a switch installation in a commercial building. Where switches control lighting loads supplied by a grounded general-purpose branch circuit, a grounded circuit conductor is required at the switch location for which of the following areas?

• A) A location where conductors enter the switch box through a raceway large enough for all conductors including a grounded conductor
• B) A storage closet where lighting is controlled by automatic means
• C) A location where the switch controls a receptacle load only
• D) A hallway where the switch controls a standard lighting load

What this tests: Understanding of Article 404 switch requirements and the exceptions surrounding grounded conductor requirements at switch locations.

Question 3 — Communication Systems

Which of the following listed cable types is classified as a network-powered broadband communications low-power plenum cable?

• A) BLR
• B) BLX
• C) BLP
• D) BMR

What this tests: Familiarity with NEC cable listing designations for communication systems — the kind of detail that's easy to look up if you know where to find it in the code.

Question 4 — Equipment for General Use

For generators installed in other than one- and two-family dwelling units, a remote emergency stop switch is required for generators with a rating greater than what value?

• A) 15 kW
• B) 50 kW
• C) 25 kW
• D) 10 kW

What this tests: Generator installation requirements under Article 445, specifically the threshold that triggers the remote stop requirement.

Question 5 — Communication Systems

You are a master electrician overseeing a cable installation in a commercial building. A technician asks whether CATV-type coaxial cables may be placed in the same junction box as 120V power conductors. Under what condition, if any, is this permitted?

• A) Only when the power conductors supply the communications distribution equipment and a minimum 6 mm (1/4 in.) separation is maintained within the enclosure
• B) Only when the CATV cable is plenum-rated
• C) It is never permitted under any circumstances
• D) Only when the junction box is listed for dual use

What this tests: Separation requirements between power conductors and communications cables — a practical installation scenario where the wrong answer could create a real safety problem.

What Types of Questions to Expect

Our full practice exam draws from a pool of 559 questions across all eight topic areas. Here's what each section covers and how many practice questions we offer:

• General Electrical Knowledge (95 questions): Ohm's Law calculations, series circuit math, NEC chapter organization, and parsing mandatory versus permissive code language. Some questions are pure calculation; others test whether you understand the code's structure.
• Wiring and Protection (125 questions): Ampacity table lookups with correction and adjustment factors, grounding electrode system design, overcurrent device sizing, and underground wiring cover depth requirements. Expect calculation-heavy and scenario-based questions.
• Wiring Methods and Materials (100 questions): Box fill math, conductor count rules, support and securing requirements, and cable protection scenarios. Many questions present a specific installation situation and ask whether it complies.
• Equipment for General Use (110 questions): Practical questions about switch wiring, luminaire placement, receptacle grounding, and flexible cord limitations. Scenario-based and detail-oriented.
• Special Occupancies (55 questions): Hazardous location classification, health care facility wiring requirements, and commercial garage area classification. Expect both definitional questions and application scenarios.
• Special Equipment (30 questions): Crane and hoist wiring methods, disconnecting means, elevator circuit sizing, and generator installation details.
• Special Conditions (29 questions): Solar PV circuit requirements, rapid shutdown, protection techniques for hazardous locations, and health care facility branch types.
• Communication Systems (15 questions): Cable listing designations, grounding requirements, separation from power conductors, and aerial clearances.

Study Materials for the Idaho Master Electrician Exam

You're allowed to bring reference materials into the exam. Having the right books — and knowing how to use them — is a genuine competitive advantage.

Required:

• National Electrical Code 2023 — This is the primary reference for the exam. Idaho currently references the NEC 2023, so make sure you have the right edition. Tab it, highlight it, and practice finding articles quickly.
• Ugly's Electrical References 2020 — A compact field reference that's great for quick lookups of wire sizes, conduit fill, and common formulas. Experienced electricians swear by it for a reason.

Highly Recommended:

• Ferm's Fast Finder Index — A cross-referenced index that helps you locate NEC content by topic rather than by article number. When you know what you're looking for but aren't sure where it lives in the code, this saves real time.
• Key Word Index by Tom Henry — Another NEC index tool, organized alphabetically by keyword. Many test-takers use both this and Ferm's and decide which one suits their lookup style better.

The index books are especially worth buying if the open-book format is new to you. An extra 60 seconds per question adds up fast across 100 questions.

Study Tips for the Idaho Master Electrician Exam

Prioritize by weight. Wiring and Protection and the two Equipment/Wiring Methods sections together account for 65 of the 100 questions. Nail those three areas and you're most of the way to a passing score before you even get to the specialized topics.

Practice your NEC navigation. Timed practice under open-book conditions is the only way to get faster. Set a stopwatch and look up specific code sections until you can find them in under 30 seconds.

Do the math by hand. Box fill, ampacity, Ohm's Law — these calculations show up regularly and calculators are typically permitted, but you need to know the right formula and table before the calculator helps you.

Read questions carefully. Master electrician exam questions often include scenarios with one detail that changes the answer entirely ("other than one- and two-family dwelling units," for example). Slow down on scenario questions.

Don't skip Special Occupancies. Eleven questions is meaningful. Hazardous location classification and health care facility rules are learnable — don't leave those points on the table.

Frequently Asked Questions

How many questions are on the Idaho Master Electrician Exam?
The exam has 100 scored questions. You need to answer 75 of them correctly to pass — a 75% passing score.

How long do I have to complete the exam?
You get 270 minutes (4.5 hours). That's about 2.7 minutes per question on average, which is workable if you're practiced at NEC lookups. Don't spend 10 minutes on a single question — mark it and come back.

Is the Idaho Master Electrician Exam open book?
Yes. You can bring approved references including the NEC. Check the official exam bulletin for the current list of permitted materials and any restrictions on tabbing or highlighting.

What NEC edition does Idaho use?
Idaho references the NEC 2023. Make sure you're studying and purchasing the correct edition — the NEC 2023 is the one to have.

What's the best way to prepare?
Combine code study with timed practice questions. Use our free practice exam to gauge your starting point, then work through the full practice exam to identify weak areas by topic. Focus extra study time on Wiring and Protection, Wiring Methods, and Equipment for General Use, since those three sections carry the most weight.

Ready to Start Preparing?

The Idaho Master Electrician license opens real doors — higher-value work, the ability to pull permits, and the credential to run your own electrical contracting operation. The exam is rigorous, but 100 questions in 4.5 hours with an open-book format is very manageable if you show up prepared.

Start right now with our free practice exam — 10 questions, no account required, no payment. Get a feel for the format and see which topics need the most attention. When you're ready to go deeper, upgrade to the full practice exam for a complete 100-question simulation with a detailed score breakdown by topic. Good luck — you've got this.