The exam format and the references allowed

With her authorization on the way, Megan turned to the exam itself. Ben Adeyemi, Boone Ridge's estimator, had passed the Iowa master exam four years earlier and still remembered the moment the clock appeared on the screen. "It is a long day with one book," he told her. "The people who fail usually know the material. They just spend twenty minutes hunting for one table and then rush the last thirty questions." This lesson explains what the exam looks like, what you may bring and how to plan your time.

The shape of the master exam

The Iowa master exam is a computer-based, multiple-choice exam given at a PSI test center. According to the 2025 bulletin it contains 100 scored questions and 10 unscored pretest questions, for 110 questions in all. The pretest questions are new items being tried out for future exams. They look exactly like the scored questions and are mixed in with them, so a candidate should answer every question as if it counts. The bulletin's timing table allows 240 minutes for the master exam, with additional time listed for the tutorial and administration. Plan your pacing on the 240 minutes.

A score of 70 is passing. Megan's arithmetic was quick: 110 questions in 240 minutes is a little over two minutes a question on average. That sounds generous until you remember that a feeder calculation or a service load can take six or eight minutes, and that many questions require finding a specific section, exception or table entry before you can answer.

The one book you may bring

The master exam is open book, but with only one book. The bulletin allows the 2023 edition of the National Electrical Code or the 2023 NEC Handbook, which contains the code text along with explanations and illustrations. Many candidates prefer the plain code book because it is lighter and the pages are easier to scan, while others like the Handbook's diagrams. Whichever you choose, practice with that book and only that book.

The bulletin sets rules for what the book may contain. Candidates may highlight, underline and use permanent index tabs. They may not write notes, formulas or examples in the book, and loose papers or removable notes are not allowed. Popular pocket reference guides, such as the widely used electrical formula and table handbooks, are specifically not allowed. Proctors inspect the book before the exam begins, and a book with prohibited material can be refused, which leaves the candidate to test without it. Megan bought a new 2023 NEC with a set of permanent tabs and never wrote a single note in it.

Because only the code may come in, anything else a candidate needs must be in their head. That includes formulas for voltage drop and three-phase power, the steps of a service load calculation, the layout of the code itself, and any Iowa law and business material listed in the content outline. If the outline in your bulletin lists Iowa laws and rules, the board's chapter 103 and chapter 401 to 404 material in this course is what you study for it, because you will not have those documents at the test center.

Tabbing the book

Permanent tabs save time, but only if you know them. Ben's rule was to tab the places you go most often and to stop there. A book with a hundred tabs is as slow as a book with none. Megan tabbed the start of each chapter, Article 100, the branch circuit, feeder and service calculation articles, the conductor ampacity tables, the overcurrent protection article, the grounding and bonding article, the motor article, the raceway fill material and the tables in Chapter 9. She also highlighted the exceptions she had missed in practice, so that her eye would stop on them.

The calculator

A calculator is allowed and is essential for a master exam. The bulletin requires a silent, battery-powered calculator without a printing tape, alphabetic keyboard, programmable memory or communication functions, and it prohibits phones and watches as calculators. Basic scientific calculators of the kind sold for trade exams are the safe choice. Practice with the calculator you will bring, including the square root of three, which appears in every three-phase calculation and is worth knowing as roughly 1.732.

What the questions test

The bulletin's content outline lists the subject areas on the master exam and the number of questions drawn from each. For a master exam these typically include general code knowledge and definitions, services, feeders and branch circuits, load calculations, wiring methods and materials, equipment for general use, special occupancies and equipment, motors and transformers, grounding and bonding, and electrical theory. The outline is the best guide to where your study time should go, so read it before you plan and match your practice to it.

Master questions differ from journeyman questions mainly in depth. A journeyman question might ask for the minimum size of a conductor for a given load. A master question is more likely to ask for the minimum service size for a building after a full load calculation with demand factors, or for the correct overcurrent protection for a motor branch circuit and its feeder. They also tend to combine several steps, so an early mistake leads to a wrong final answer that may well appear among the choices.

A pacing plan

Ben taught Megan a two-pass plan. On the first pass she would answer every question she could answer in about a minute, flag the long ones and keep moving. On the second pass she would work the flagged calculations and code searches carefully. The last stretch would be for review of flagged answers and for making sure no question was left blank, because an unanswered question is always wrong while a guess has a chance.

# Pacing checkpoints for a 240-minute, 110-question exam (illustrative)
total_minutes, questions = 240, 110
print("average minutes per question:", round(total_minutes / questions, 2))
plan = [("first pass ends", 90), ("second pass ends", 215), ("review ends", 240)]
for label, minute in plan:
    print(f"{label:18} at minute {minute:3}  ({total_minutes - minute} minutes left)")
# How far behind is too far? Check at minute 60 on the first pass.
answered_at_60 = 58
on_pace = answered_at_60 >= questions * 60 / 90 * 0.8
print("on pace at minute 60:", on_pace)

average minutes per question: 2.18
first pass ends    at minute  90  (150 minutes left)
second pass ends   at minute 215  (25 minutes left)
review ends        at minute 240  (0 minutes left)
on pace at minute 60: False

Practice that matches the real thing

The most useful practice copies the test conditions. Megan took full timed practice exams at the kitchen table with her tabbed code book, her exam calculator and nothing else, and logged every miss by code area and by cause. Some misses were knowledge gaps. Others were reading errors, such as missing the word not or an exception, and some were time problems. The log told her which chapters to study and which habits to fix. Lesson 12 returns to this method in the final weeks.

Three kinds of questions

Ben sorted the questions he remembered into three kinds, and Megan found the sorting useful in practice. The first kind is the direct lookup: a question that names a topic and asks for a value or a rule. These are fast if you know where the topic lives, which is why the index and the tabs matter. Start with the index entry for the key noun in the question, not with a guess at the article number, and read the whole section before choosing an answer, including its exceptions.

The second kind is the calculation: a load calculation, a conductor or overcurrent sizing, a voltage drop, a box or raceway fill, or a motor circuit. These reward a fixed routine. Note the knowns, using whatever scratch material the test center provides, decide which article governs, work the steps in order and check whether the answer must be rounded up to a standard size. Many wrong answers on the choice list are the result of one common slip, such as using the wrong demand factor or forgetting a continuous-load multiplier, so a result that matches a choice is not proof that it is right.

The third kind is the reading question, where the difficulty is the wording rather than the code. Questions may use not, except or minimum, or describe a situation in a paragraph and ask about one detail. Read the last sentence first to learn what is being asked, then read the paragraph for the facts that matter. Megan's practice log showed that reading errors cost her almost as many points as knowledge gaps in her first three practice exams, and that they nearly disappeared once she made the habit automatic.

When a question will not come

Every candidate meets a question that will not yield. The two-pass method handles most of them, but on the second pass a question can still eat time. Ben's limit was six minutes. If a question was still open after six minutes, he chose the most reasonable answer, flagged it and moved on, returning only if time remained at the end. One question is worth one point, the same as a two-minute lookup, and the minutes it steals can cost three or four answers later.

Building speed with the index

Speed in an open-book exam comes from the index more than from memory. The NEC index lists topics by key noun, so a question about receptacles in a bathroom is found under receptacles or bathrooms, not under the article number you think it might be. In the first two weeks of study Megan answered every practice question twice: once by memory and once by finding it through the index, timing the second search. Her average search time fell from about three minutes to under one, and she began to recognize the handful of index entries that led to most answers. That habit, more than any single tab, is what made the 240 minutes feel long enough.

On the day

The test center routine is predictable. Arrive early, show ID, store personal items, have the book inspected, take a short tutorial on the computer system, and begin. The clock on the screen counts down. Questions can be flagged and revisited. When time runs out, the exam ends and unanswered questions count as wrong. Many candidates find the first fifteen minutes the hardest, and Ben's advice was to start with a few quick questions to settle in rather than fight the first long calculation.