Journeyman Electrician Exam Prep: Complete Study Guide
Everything you need to know to pass the journeyman electrician licensing exam on your first attempt. Master NEC code navigation, electrical theory, calculations, and proven test-taking strategies.
What to Expect on the Journeyman Electrician Exam
The journeyman electrician licensing exam is the gateway to your career as a fully licensed electrician. While specific requirements vary by state and testing body, the exam format is remarkably consistent across most jurisdictions. Understanding the structure before you sit down is one of the most important steps in your preparation.
Most states use exams administered by PSI, Prometric, or a state-specific testing agency. The two most common standardized exams are developed by PSI and based heavily on the National Electrical Code (NEC). Some states write their own exams, but the content areas remain fundamentally the same.
Exam Format Overview
| Parameter | Typical Value |
|---|---|
| Number of Questions | 80 - 100 multiple choice |
| Time Allowed | 4 - 5 hours |
| Passing Score | 70% - 75% (varies by state) |
| Reference Allowed | NEC code book (tabbed, no notes) |
| Calculator | Non-programmable, basic scientific |
| Primary Code Cycle | NEC 2023 (check your state) |
Content Breakdown by Topic Area
While the exact weighting varies, here is a typical distribution of questions by topic on most journeyman exams:
| Topic Area | Approx. % of Exam | Key NEC Articles |
|---|---|---|
| Grounding & Bonding | 15 - 20% | Article 250 |
| Branch Circuits & Feeders | 12 - 15% | Articles 210, 215 |
| Overcurrent Protection | 10 - 12% | Article 240 |
| Wiring Methods | 10 - 15% | Articles 300-392 |
| Motors & Controllers | 8 - 12% | Article 430 |
| Services | 8 - 10% | Article 230 |
| Load Calculations | 8 - 10% | Article 220 |
| Boxes & Fittings | 5 - 8% | Articles 314, 370 |
| Electrical Theory | 5 - 10% | General knowledge |
Key NEC Articles You Must Master
The NEC is a massive document, but the journeyman exam focuses heavily on a core set of articles. You should be able to navigate these articles quickly and accurately. Knowing where to find information is just as important as memorizing it, since you will have your code book available during the exam.
The "Big Five" Articles
These five articles collectively account for the majority of exam questions. Build your study plan around mastering these first.
Article 250 - Grounding and Bonding
The single most tested article. Know sizing tables (250.66, 250.122), grounding electrode systems, bonding requirements, and equipment grounding conductor rules.
Article 210 - Branch Circuits
GFCI/AFCI requirements, receptacle outlet spacing, circuit ratings, and permissible loads. Expect 8-12 questions on this article alone.
Article 240 - Overcurrent Protection
Standard ampere ratings (240.6), next size up rule (240.4(B)), tap rules (240.21), and coordination with conductor sizing.
Article 430 - Motors
Motor FLC tables (430.247-250), overload protection sizing, branch circuit protection, feeder sizing, and disconnecting means.
Article 220 - Branch-Circuit, Feeder, and Service Load Calculations
Demand factors, general lighting loads (Table 220.12), appliance circuits, and optional calculation methods for dwellings.
Critical Supporting Articles
- Article 110 - Requirements for Electrical Installations (working space clearances 110.26, temperature ratings)
- Article 230 - Services (service entrance, disconnecting means, overcurrent protection)
- Article 300 - General Requirements for Wiring Methods and Materials
- Article 310 - Conductors for General Wiring (ampacity tables, derating)
- Article 314 - Outlet, Device, Pull, and Junction Boxes (box fill calculations)
- Article 334 - Nonmetallic-Sheathed Cable (NM/Romex rules)
- Article 344-358 - Raceway articles (EMT, RMC, IMC, PVC, FMC)
- Article 408 - Switchboards, Switchgear, and Panelboards
- Article 422 - Appliances
- Article 480 - Storage Batteries
Electrical Theory Review
While the exam is primarily code-based, you will encounter questions that test your understanding of fundamental electrical theory. These questions do not require code book lookups -- you either know the theory or you do not. That makes them both fast to answer and easy to lose points on if you are unprepared.
Essential Formulas Reference
Ohm's Law:
E = I x R | I = E / R | R = E / I
Power (DC & Single-Phase AC):
P = E x I | P = I2 x R | P = E2 / R
Power (3-Phase):
P = E x I x 1.732 x PF
Voltage Drop:
VD = (2 x K x I x D) / CM
K = 12.9 (copper) or 21.2 (aluminum) | D = distance in feet | CM = circular mils
Apparent Power (VA):
VA = E x I | kVA = (E x I) / 1000
Power Factor:
PF = True Power (W) / Apparent Power (VA)
Efficiency:
Eff = (Power Out / Power In) x 100%
Series vs Parallel Circuits
These fundamental circuit concepts appear regularly on the exam. You need to be comfortable calculating total resistance, current, and voltage in both configurations.
Series Circuit Rules
- Rtotal = R1 + R2 + R3 ...
- Itotal = I1 = I2 = I3 (same everywhere)
- Etotal = E1 + E2 + E3 (voltage divides)
- Total resistance increases
- One open = entire circuit stops
Parallel Circuit Rules
- 1/Rt = 1/R1 + 1/R2 + 1/R3 ...
- Etotal = E1 = E2 = E3 (same everywhere)
- Itotal = I1 + I2 + I3 (current divides)
- Total resistance decreases
- One open = other paths still work
Conductor Properties You Should Know
| Property | Copper | Aluminum |
|---|---|---|
| K Factor (resistivity) | 12.9 | 21.2 |
| Weight | Heavier | ~30% weight of copper |
| Conductivity | 100% (reference) | ~61% of copper |
| Typical Sizing Rule | Reference size | Two sizes larger than Cu |
NEC Code Navigation Tips
The exam is open-book, which means your ability to find information quickly is paramount. Electricians who tab and index their code book effectively can answer code-lookup questions in under 60 seconds. Those who do not may spend 5 minutes or more per question -- and with 80+ questions in 4 hours, that math does not work in your favor.
Tabbing Strategy
Use pre-made NEC tabs or create your own. At minimum, tab every article you will reference frequently. Most exam veterans recommend the following tabbing approach:
Priority Tab Locations
Tab 1: Table of Contents
Tab 2: Article 90 (scope)
Tab 3: Article 100 (definitions)
Tab 4: Article 110 (requirements)
Tab 5: Table 110.26(A)(1)
Tab 6: Article 200 (grounded conductors)
Tab 7: Article 210 (branch circuits)
Tab 8: Article 220 (load calcs)
Tab 9: Article 230 (services)
Tab 10: Article 240 (overcurrent)
Tab 11: Article 250 (grounding)
Tab 12: Article 300 (wiring methods)
Tab 13: Article 310 / Table 310.16
Tab 14: Article 314 (boxes)
Tab 15: Article 334 (NM cable)
Tab 16: Article 430 (motors)
Tab 17: Chapter 9 Tables
Tab 18: Table 310.16 (ampacity)
Tab 19: Annex D (examples)
Tab 20: Index
How to Read an NEC Reference Quickly
NEC section numbers follow a logical hierarchy. Understanding the numbering system speeds up your lookups dramatically:
- Article - The main topic (e.g., Article 250 = Grounding)
- Part - Roman numeral subdivisions within an article (Part I, Part II, etc.)
- Section - Specific requirement (e.g., 250.122 = Size of EGCs)
- Subsection - Letters in parentheses further break down rules (e.g., 250.122(B))
- Exception - Conditions that modify the general rule
Load Calculation Practice
Load calculations are one of the most heavily tested areas on the journeyman exam. You need to be comfortable performing both standard and optional calculations for dwelling units, and understand commercial load calculation methods as well.
Residential Standard Calculation (Article 220)
Step-by-Step: Standard Dwelling Load Calculation
Step 1: General Lighting Load
Floor area (sq ft) x 3 VA/sq ft [Table 220.12]
Step 2: Add Small Appliance Circuits
Minimum 2 circuits x 1,500 VA = 3,000 VA [210.11(C)(1)]
Step 3: Add Laundry Circuit
Minimum 1 circuit x 1,500 VA = 1,500 VA [210.11(C)(2)]
Step 4: Apply Demand Factors [Table 220.42]
First 3,000 VA at 100%
Remainder at 35%
Step 5: Add Fixed Appliances
If 4 or more fixed appliances: apply 75% demand factor
Step 6: Add Largest Motor at 125%
Per 220.18 and 430.22
Step 7: Add Dryer Load [Table 220.54]
5,000 VA or nameplate rating, whichever is larger
Step 8: Add Cooking Equipment [Table 220.55]
Apply column demand factors based on number of units
Step 9: Add HVAC (largest of heating or cooling)
Per 220.60 - do not add both
Practice Problem: Dwelling Unit Load Calculation
Given:
- 1,800 sq ft dwelling
- 2 small appliance circuits + 1 laundry circuit
- Electric range: 12 kW
- Electric dryer: 5.5 kW
- Water heater: 4,500 watts
- Dishwasher: 1,500 watts
- Disposal: 900 watts
- A/C: 5,000 watts
- Electric heat: 4,000 watts
- 240V, single-phase service
Solution:
General Lighting:
1,800 sq ft x 3 VA = 5,400 VA
Small Appliance + Laundry:
3,000 VA + 1,500 VA = 4,500 VA
Subtotal:
5,400 + 4,500 = 9,900 VA
Apply Table 220.42 Demand:
First 3,000 VA at 100% = 3,000 VA
Remaining 6,900 VA at 35% = 2,415 VA
Net general lighting = 5,415 VA
Range [Table 220.55, Column C]:
12 kW range, 1 unit = 8,000 VA demand
Dryer [Table 220.54]:
5,500 VA (nameplate > 5,000 VA minimum)
Fixed Appliances (3 items - no 75% demand):
Water heater: 4,500 VA
Dishwasher: 1,500 VA
Disposal: 900 VA
Subtotal: 6,900 VA
HVAC (larger of A/C or heat):
A/C: 5,000 VA (larger, use this)
Total Calculated Load:
5,415 + 8,000 + 5,500 + 6,900 + 5,000 = 30,815 VA
Service Size:
I = 30,815 VA / 240V = 128.4 amps
Minimum 150A service required
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Grounding and Bonding Essentials
Article 250 is the most heavily tested article on the journeyman exam. You can expect 15-20% of all questions to come from grounding and bonding topics. Understanding the distinction between grounding (connection to earth) and bonding (creating an effective fault current path) is fundamental.
Key Grounding Concepts
- Grounding Electrode System (250.50) - All electrodes present at a building must be bonded together to form the grounding electrode system
- Grounding Electrode Conductor (GEC) sizing - Use Table 250.66, based on the size of the largest service-entrance conductor
- Equipment Grounding Conductor (EGC) sizing - Use Table 250.122, based on the rating of the overcurrent device
- Main bonding jumper (250.28) - Connects the grounded conductor (neutral) to the equipment grounding bus at the service
- Bonding of service equipment (250.92) - Requires specific bonding methods; standard locknuts alone are insufficient
GEC Sizing Quick Reference
Table 250.66 - Grounding Electrode Conductor (Copper)
| Service Conductor Size (Cu) | GEC Size (Cu) |
|---|---|
| #2 AWG or smaller | #8 AWG |
| #1 or 1/0 AWG | #6 AWG |
| 2/0 or 3/0 AWG | #4 AWG |
| Over 3/0 through 350 kcmil | #2 AWG |
| Over 350 through 600 kcmil | #1/0 AWG |
| Over 600 through 1100 kcmil | #2/0 AWG |
Practice Problem: Grounding Conductor Sizing
Question:
A 200-amp service uses 2/0 AWG copper service-entrance conductors. What is the minimum size copper grounding electrode conductor and the minimum size copper equipment grounding conductor for a 30-amp branch circuit?
Answer:
GEC: Per Table 250.66, for 2/0 AWG copper service conductors, the minimum GEC is #4 AWG copper.
EGC: Per Table 250.122, for a 30-amp overcurrent device, the minimum EGC is #10 AWG copper.
Motor Calculations
Motor calculations are a consistent exam topic because they involve multiple NEC sections working together. The key to motor questions is understanding that you must use the Full-Load Current (FLC) from NEC tables -- not the nameplate amperage -- for sizing branch circuit conductors and overcurrent protection.
Motor Calculation Steps
Step 1: Find FLC from NEC Tables
Table 430.247 (DC) | Table 430.248 (1-phase AC) | Table 430.249 (2-phase AC) | Table 430.250 (3-phase AC)
Step 2: Size Branch Circuit Conductors (430.22)
Minimum conductor ampacity = FLC x 125%
Step 3: Size Overload Protection (430.32)
Service factor 1.15+ or temp rise 40C: nameplate FLA x 125% | All others: nameplate FLA x 115%
Step 4: Size Branch Circuit Protection (430.52)
Dual-element fuse: FLC x 175% | Inverse-time breaker: FLC x 250% | Instantaneous-trip breaker: FLC x 800%
Step 5: Size Disconnect (430.110)
Minimum 115% of motor FLC
Practice Problem: Motor Branch Circuit
Question:
Size the branch circuit conductors, overcurrent protection (dual-element fuse), and disconnect for a 10 HP, 230V, 3-phase motor with a 1.15 service factor.
Solution:
Step 1: FLC from Table 430.250
10 HP, 230V, 3-phase = 28 amps
Step 2: Conductor size (430.22)
28A x 1.25 = 35 amps minimum
#8 AWG copper THHN (50A @ 75C per Table 310.16)
Step 3: Overload protection (430.32)
SF = 1.15, so: nameplate FLA x 125%
28A x 1.25 = 35 amps
35-amp overload relay
Step 4: Branch circuit fuse (430.52, dual-element)
28A x 1.75 = 49 amps
Next standard size: 50-amp dual-element fuse
Step 5: Disconnect (430.110)
28A x 1.15 = 32.2 amps minimum
Minimum 40-amp disconnect (next standard size)
Raceway and Conductor Sizing
Conduit fill calculations appear frequently on the exam. You need to know the maximum fill percentages and be able to use Chapter 9 tables to determine the correct conduit size for a given number of conductors.
Conduit Fill Percentages (Chapter 9, Table 1)
| Number of Conductors | Maximum Fill (%) |
|---|---|
| 1 conductor | 53% |
| 2 conductors | 31% |
| 3 or more conductors | 40% |
Ampacity and Derating
Table 310.16 is the most referenced table in the NEC. You should be able to find ampacity values quickly and apply correction and adjustment factors.
- Temperature correction (310.15(B)) - Reduce ampacity when ambient temperature exceeds 30 degrees C
- Conductor bundling adjustment (310.15(C)(1)) - When more than 3 current-carrying conductors are in a raceway, apply adjustment factors from Table 310.15(C)(1)
- Terminal temperature limits - Most equipment is rated for 75 degrees C. Use the 75 degrees C column of Table 310.16 unless all terminations are rated for higher temperature
Derating Quick Reference
Table 310.15(C)(1) - Conductor Bundling Adjustment Factors
| Current-Carrying Conductors | Adjustment Factor |
|---|---|
| 4 - 6 | 80% |
| 7 - 9 | 70% |
| 10 - 20 | 50% |
| 21 - 30 | 45% |
| 31 - 40 | 40% |
| 41 and above | 35% |
Box Fill Calculations
Box fill questions based on NEC 314.16 are common on the journeyman exam. The key is understanding how to count conductors and convert the count into required box volume.
Conductor Counting Rules (314.16(B))
| Item in Box | Conductor Equivalent |
|---|---|
| Each conductor entering the box | 1 (based on conductor size) |
| All internal cable clamps (combined) | 1 (based on largest conductor) |
| All equipment grounding conductors (combined) | 1 (based on largest EGC) |
| Each yoke/strap (device) | 2 (based on largest conductor connected) |
| Conductors originating and ending in box | 1 (based on conductor size) |
| Conductors passing through (unbroken) | 1 (based on conductor size) |
Volume per Conductor (Table 314.16(B))
| Wire Size | Volume (cu. in.) |
|---|---|
| #14 AWG | 2.00 |
| #12 AWG | 2.25 |
| #10 AWG | 2.50 |
| #8 AWG | 3.00 |
| #6 AWG | 5.00 |
Practice Problem: Box Fill
Question:
A device box contains: two 14/2 NM cables (4 insulated conductors + 2 grounds), one single-gang receptacle, and internal cable clamps. What is the minimum box volume?
Solution:
4 insulated #14 conductors = 4 x 2.00 = 8.00 cu. in.
All grounds (1 count) = 1 x 2.00 = 2.00 cu. in.
All clamps (1 count) = 1 x 2.00 = 2.00 cu. in.
1 device (2 counts) = 2 x 2.00 = 4.00 cu. in.
Total minimum volume = 16.00 cu. in.
Use a single-gang 18 cu. in. device box (3 x 2 x 3-1/2 deep) or larger.
Study Strategies and Time Management
Passing the journeyman exam requires a structured study plan. Most successful candidates study for 3-6 months before the exam, dedicating at least 1-2 hours daily. Here is a proven approach to maximize your preparation time.
12-Week Study Plan
Code Book Familiarization
Tab your code book, learn the table of contents, practice finding articles by number. Read Article 90 and Article 100 completely.
Electrical Theory Review
Ohm's law, power formulas, series/parallel circuits, transformer theory, and AC fundamentals. These questions do not require a code book.
Grounding & Bonding (Article 250)
The single most tested topic. Memorize Tables 250.66 and 250.122. Understand grounding electrode systems and main bonding jumper rules.
Branch Circuits, Services, Overcurrent Protection
Articles 210, 215, 230, and 240. GFCI/AFCI requirements, service sizing, tap rules, and standard fuse/breaker ratings.
Motors, Load Calculations, Wiring Methods
Motor FLC tables, overload and branch circuit protection sizing, dwelling unit load calculations, conduit fill, and box fill.
Practice Exams & Review
Take full-length timed practice exams. Review weak areas. Focus on speed and code book navigation efficiency.
Study Checklist
Pre-Exam Readiness Checklist
[ ] NEC code book properly tabbed
[ ] Can navigate to any article in under 15 seconds
[ ] Memorized Ohm's law and power formulas
[ ] Comfortable with series/parallel circuits
[ ] Can perform dwelling load calculations
[ ] Know conductor bundling derating factors
[ ] Understand conduit fill percentages
[ ] Can size GEC from Table 250.66
[ ] Can size EGC from Table 250.122
[ ] Motor branch circuit sizing mastered
[ ] Box fill calculations accurate
[ ] Passed 3+ practice exams at 80%+
[ ] Reviewed all missed practice questions
[ ] Calculator batteries fresh
Practice Question Examples
The best way to prepare is to practice with questions in the same format you will see on the exam. Here are sample questions covering major topic areas. Try to answer each one before looking at the solution.
Question 1: Branch Circuits
What is the maximum number of receptacle outlets permitted on a 20-amp, 120-volt general purpose branch circuit in a commercial occupancy?
Answer:
13 receptacle outlets. Per NEC 210.21(B)(2) and 220.18, each receptacle is calculated at 180 VA. A 20A x 120V circuit = 2,400 VA. At 180 VA per receptacle: 2,400 / 180 = 13.3, rounded down to 13 receptacles.
Question 2: Grounding
What is the minimum size copper equipment grounding conductor required for a circuit protected by a 60-amp overcurrent device?
Answer:
Per Table 250.122, for a 60-amp overcurrent device, the minimum copper EGC is #10 AWG.
Question 3: Overcurrent Protection
What are the standard ampere ratings for fuses and inverse time circuit breakers as listed in the NEC?
Answer:
Per 240.6(A): 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 125, 150, 175, 200, 225, 250, 300, 350, 400, 450, 500, 600, 700, 800, 1000, 1200, 1600, 2000, 2500, 3000, 4000, 5000, and 6000 amperes. Memorize at least the first 20 values -- they appear in many calculation questions.
Question 4: Voltage Drop
A 120V circuit uses #12 AWG copper conductors (6,530 CM) to supply a 16-amp load 100 feet from the panel. What is the voltage drop?
Answer:
VD = (2 x K x I x D) / CM
VD = (2 x 12.9 x 16 x 100) / 6,530
VD = 41,280 / 6,530
VD = 6.32 volts (5.27%)
This exceeds the NEC recommended 3% for branch circuits (210.19(A) Informational Note No. 4). Consider upsizing to #10 AWG.
Question 5: Conduit Fill
What is the maximum number of #12 AWG THHN conductors permitted in a 3/4-inch EMT conduit?
Answer:
Per NEC Chapter 9, Table C.1 (for EMT with THHN conductors), a 3/4-inch EMT can hold a maximum of 16 conductors of #12 AWG THHN. You can also calculate this manually using Chapter 9 Tables 4 and 5, applying the 40% fill rule for 3+ conductors.
Test Day Tips
Your performance on exam day depends on more than just knowledge. Managing your time, energy, and strategy can make the difference between passing and failing.
Before the Exam
- Verify your code book - Make sure it has no handwritten notes, loose pages, or unauthorized materials. Some testing sites inspect your book before you enter.
- Bring a backup calculator - If your calculator fails, you cannot leave to buy a new one. Non-programmable scientific calculators only.
- Get a good night's sleep - A rested mind navigates code faster. Do not cram the night before.
- Eat a solid meal - You may be sitting for 4+ hours. Bring water and a snack if allowed.
- Arrive early - Allow time for check-in, ID verification, and settling in.
During the Exam
Strategy 1: Three-Pass Approach
First pass: Answer all questions you know immediately (theory, memorized facts). Second pass: Answer code-lookup questions. Third pass: Tackle calculation-heavy problems.
Strategy 2: Time Budgeting
With 80 questions in 4 hours, you have 3 minutes per question. Theory questions should take under 1 minute, leaving more time for calculations. Never spend more than 5 minutes on any single question.
Strategy 3: Eliminate and Guess
If you cannot find the answer, eliminate obviously wrong choices first. There is no penalty for guessing, so never leave a question blank.
Strategy 4: Read the Question Carefully
Many exam questions are missed because of misread details -- copper vs aluminum, single-phase vs three-phase, minimum vs maximum. Circle key words in the question.
Strategy 5: Trust Your Code Book
When in doubt, look it up. The answer is almost always in the NEC. Do not rely solely on memory for code-specific questions.
Common Exam Mistakes to Avoid
Using Nameplate Amps for Motors
Always use FLC from NEC tables for branch circuit and protection sizing. Nameplate is only for overload protection.
Wrong Temperature Column
Most terminations are rated 75 degrees C. Using the 90 degrees C column when terminations are 75 degrees C gives wrong answers.
Forgetting Demand Factors
Load calculations require demand factors from Tables 220.42, 220.54, and 220.55. Missing these inflates your calculated load.
Mixing Up GEC and EGC Tables
Table 250.66 sizes GECs based on service conductor size. Table 250.122 sizes EGCs based on overcurrent device rating. Do not confuse them.
Additional Resources for Exam Preparation
Beyond studying the NEC directly, these additional resources can reinforce your learning and fill knowledge gaps:
- Mike Holt's Exam Preparation textbook - The industry standard study guide with detailed explanations and practice questions
- Tom Henry's Key to the NEC - Excellent for learning code book navigation and understanding NEC structure
- State-specific study guides - Some states have unique requirements beyond the NEC; check your state's licensing board
- Practice exam software - Timed practice exams simulate real test conditions and identify weak areas
- Study groups - Explaining concepts to others reinforces your own understanding
- Ampora app - Use AI-powered NEC code lookups to verify your understanding and practice finding code references quickly
Use Ampora to Accelerate Your Exam Prep
Preparing for the journeyman exam means being able to find NEC code references quickly and perform calculations accurately under pressure. Ampora's AI-powered code lookup and built-in electrical calculators let you practice code navigation, verify your calculation work, and build the speed you need to pass with confidence. Download it free and start studying smarter today.
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