10 NEC Articles That Appear on Every Texas Journeyman Exam

The NEC is over 1,000 pages long, but the Texas journeyman electrician exam does not test every page equally. Certain articles show up again and again because they cover the foundational knowledge that every working electrician needs. If you know these 10 articles well, you are already covering the majority of what the exam tests.

This guide breaks down each article, tells you exactly what the exam focuses on within it, and gives you practical tips for finding answers quickly on test day.

Why Knowing the High-Frequency Articles Matters

The TDLR content outline tells us the percentage breakdown of exam topics, and when you map those topics back to NEC articles, clear patterns emerge. Roughly 80% of exam questions trace back to about 10 core articles and their associated tables.

Since the exam is open-book (you bring your own 2023 NEC codebook), the goal is not to memorize these articles word for word. The goal is to know them well enough that you can find the right answer in under two minutes per question. That means knowing the structure of each article, understanding the key tables, and being able to navigate to the right section quickly.

1. Article 210: Branch Circuits

Why it matters: Branch circuits are the foundation of electrical installations. Article 210 covers requirements for branch circuits, including ratings, outlet provisions, and GFCI/AFCI protection requirements. It accounts for a significant portion of the NEC Knowledge section.

What the exam tests:

GFCI protection requirements (210.8) and where GFCIs are required in dwelling units and other locations
AFCI protection requirements (210.12)
Branch circuit ratings and permissible loads (210.3, 210.23)
Receptacle outlet requirements for dwelling units (210.52), including spacing rules for countertops, bathrooms, and outdoor areas
Maximum cord-and-plug connected load on a branch circuit

Study tip: Create a quick-reference sheet of all the locations that require GFCI protection under 210.8(A) for dwelling units and 210.8(B) for other than dwelling units. These lists change with each NEC cycle and are heavily tested.

Tab this: Section 210.8, Table 210.24, Section 210.52

2. Article 220: Branch-Circuit, Feeder, and Service Load Calculations

Why it matters: Article 220 is the backbone of the Calculations portion of the exam. Load calculations determine service size, feeder size, and branch circuit requirements for every type of building. This article appears on both portions of the exam.

What the exam tests:

General lighting load calculations using Table 220.12
Small appliance and laundry branch circuit loads (220.52, 220.53)
Demand factors for general lighting (Table 220.42) and specific appliances
Standard vs. optional dwelling unit load calculations (Part III vs. Part IV)
Demand factors for dryers (Table 220.54), cooking equipment (Table 220.55), and heating/cooling loads (220.60)

Study tip: Practice the full dwelling unit load calculation from start to finish until you can complete one in under 15 minutes. The exam will give you a scenario and expect you to apply the correct demand factors from the right tables.

Tab this: Table 220.12, Table 220.42, Table 220.54, Table 220.55

Practice load calculations with our free calculator

3. Article 250: Grounding and Bonding

Why it matters: Grounding and bonding is one of the most complex topics in the NEC and one of the most commonly missed on the exam. It covers how electrical systems are connected to earth and how equipment is bonded for safety. TDLR allocates 7.5% of the NEC Knowledge portion specifically to this topic.

What the exam tests:

System grounding requirements and grounding electrode systems (250.50)
Equipment grounding conductor (EGC) sizing using Table 250.122
Grounding electrode conductor (GEC) sizing using Table 250.66
Main bonding jumper and system bonding jumper requirements
Grounding of separately derived systems (250.30)
When and how to bond water pipes, structural steel, and other metallic components

Study tip: Learn the difference between the grounding electrode conductor (GEC) and the equipment grounding conductor (EGC). These are sized from different tables and serve different purposes. Many exam questions test whether you know which table to use.

Tab this: Table 250.66, Table 250.122, Section 250.30, Section 250.50

4. Article 310: Conductors for General Wiring

Why it matters: Conductor sizing is the single most tested calculation topic. Article 310 and its associated tables tell you the ampacity of conductors based on type, temperature rating, and installation conditions. About 30% of the Calculations portion deals with conductor sizing and overcurrent protection.

What the exam tests:

Ampacity from Table 310.16 (formerly Table 310.15(B)(16) in older editions)
Temperature correction factors for ambient temperatures other than 30C
Adjustment factors for more than three current-carrying conductors in a raceway
Selecting the correct conductor size based on terminal temperature ratings (110.14(C))
When to use the 60C column vs. the 75C column for conductor selection

Study tip: The most common mistake is using the wrong temperature column. For most circuits rated 100A or less, you must use the 60C column for termination purposes, even if the conductor insulation is rated for 75C or 90C. The 90C column can only be used for ampacity derating, not for final conductor selection on most equipment.

Tab this: Table 310.16, Section 310.15(B), Section 310.15(C)

Try our conductor sizing calculator

5. Article 240: Overcurrent Protection

Why it matters: Every circuit needs overcurrent protection, and the rules for sizing and selecting fuses and circuit breakers are tested extensively. Article 240 works hand-in-hand with Article 310 because conductor sizing and overcurrent protection are interdependent.

What the exam tests:

Standard overcurrent device sizes (240.6(A))
The "next size up" rule (240.4(B)) and when it does and does not apply
Conductor protection rules, including small conductor exceptions (240.4(D))
Tap rules for feeders (240.21(B)) including the 10-foot and 25-foot tap rules
Overcurrent protection for specific equipment (transformers, motors, etc.)

Study tip: Memorize the standard overcurrent device sizes from 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 amps. This list appears in many calculation problems.

Tab this: Section 240.4, Section 240.6(A), Section 240.21(B)

6. Article 300: General Requirements for Wiring Methods and Materials

Why it matters: Article 300 sets the general rules that apply to all wiring methods. Since "Electrical Wiring Methods and Materials" is the single largest topic on the NEC Knowledge portion at 22.5%, this article and the specific wiring method articles it governs are heavily tested.

What the exam tests:

Conductor fill and derating requirements for raceways
Protection of conductors in different wiring methods
Underground installation requirements and minimum burial depths (Table 300.5)
Securing and supporting requirements
Number of conductors in boxes and raceways
Requirements for conductors of different systems in the same raceway (300.3)

Study tip: Table 300.5 (minimum cover requirements for underground installations) is a frequent exam question. Know the different depths required for rigid metal conduit, PVC, and direct burial cable under various conditions.

Tab this: Table 300.5, Section 300.3, Section 300.4

7. Article 430: Motors, Motor Circuits, and Controllers

Why it matters: Motor calculations are among the most complex problems on the Calculations portion, accounting for about 15% of that section. Article 430 is large and has a specific calculation methodology that differs from standard circuit sizing.

What the exam tests:

Finding full-load current (FLC) from NEC tables (Table 430.248 for single-phase, Table 430.250 for three-phase), not from the motor nameplate
Sizing motor branch-circuit conductors at 125% of FLC (430.22)
Sizing branch-circuit overcurrent protection per Table 430.52
Sizing motor feeder conductors and overcurrent protection for multiple motors (430.24, 430.62)
Motor overload protection (430.32)

Study tip: Always use the NEC tables for motor FLC, never the nameplate. This is a rule that trips up many test-takers. The nameplate current is used only for overload protection sizing, not for conductor or overcurrent device sizing.

Tab this: Table 430.248, Table 430.250, Table 430.52, Section 430.22

8. Article 230: Services

Why it matters: Service entrance requirements are a core topic because every building has a service, and the rules for sizing, protection, and installation are specific and heavily regulated. It falls under the "Services, Separately Derived Systems, and Remote Power Supply" category at 11.25% of the NEC Knowledge portion.

What the exam tests:

Number of services and disconnects allowed (230.2, 230.71)
Service conductor sizing and overcurrent protection
Service entrance conductor installation requirements
Clearances for overhead service drops and service laterals
Service disconnect requirements and ratings (230.79)
Service grounding requirements (ties into Article 250)

Study tip: Know the maximum number of disconnects allowed in a single grouping (six) per 230.71. Questions often present scenarios where you need to determine if a proposed service arrangement is code-compliant.

Tab this: Section 230.71, Section 230.79, Table 230.51(C)

9. Article 100: Definitions

Why it matters: Article 100 does not get tested as a standalone topic with its own percentage, but it underlies every other question on the exam. If you misunderstand a defined term, you will misinterpret the code sections that use it.

What the exam tests:

The precise definitions of terms like "accessible," "continuous load," "dwelling unit," "feeder," "service," and "branch circuit"
The difference between "grounded conductor" and "grounding conductor"
The difference between "bonding" and "grounding"
The meaning of "readily accessible" vs. "accessible" vs. "accessible, readily"
Definitions that have specific NEC meanings different from common usage

Study tip: Read through Article 100 at least twice during your study period. Pay special attention to terms that sound similar but have different meanings. On the exam, the wrong answer choices often rely on candidates confusing similar terms.

Tab this: Keep a general tab at the beginning of Article 100 for quick reference

10. Chapter 9: Tables

Why it matters: Chapter 9 contains the tables used for conduit fill calculations, conductor properties, and other values needed for the Calculations portion. Conduit and box fill accounts for roughly 10% of Calculations questions.

What the exam tests:

Table 1: Percent of conduit fill allowed (53% for 1 wire, 31% for 2 wires, 40% for 3 or more)
Table 4: Dimensions and percent area of different conduit types
Table 5: Dimensions of insulated conductors and fixture wires
Table 5A: Compact aluminum conductors
Table 8: Conductor properties (resistance values used in voltage drop calculations)
Table 9: AC resistance and reactance for 600V cables

Study tip: For conduit fill problems, you need to combine information from Tables 4 and 5 (or 5A). First find the cross-sectional area of each conductor from Table 5, multiply by the number of conductors, then find the conduit size in Table 4 that provides enough area at the correct fill percentage from Table 1.

Tab this: Table 1, Table 4, Table 5, Table 8

Practice conduit fill calculations with our free tool

How to Use This List in Your Study Plan

Now that you know which articles matter most, here is how to put this knowledge to work:

Week 1-2: Start with Articles 100 and 210. These give you the vocabulary and branch circuit foundation you need before tackling more complex topics.

Week 3-4: Move to Articles 220 and 310. These are the core of the Calculations portion and show up on the NEC Knowledge portion as well.

Week 5-6: Study Articles 250 and 240. Grounding and overcurrent protection are conceptually challenging but highly testable.

Week 7-8: Cover Articles 300, 230, and 430. These round out the major topics and include the motor calculations that many candidates struggle with.

Week 9-10: Work through Chapter 9 Tables and practice conduit fill, box fill, and voltage drop calculations.

Week 11-12: Full practice exams using all articles. Focus your review on the areas where you are still making mistakes.

The Bottom Line

You do not need to master all 1,000+ pages of the NEC to pass the Texas journeyman exam. You need to master these 10 articles and their key tables well enough to find answers quickly under time pressure. Tab your codebook at these sections, practice navigating to them, and work through practice questions that test each one.

Start practicing with our full question bank organized by NEC article and exam topic.

Sources:

Texas Department of Licensing and Regulation (TDLR) - Electrician Exam Information
TDLR - Electrician Exam Statistics, Fiscal Year 2025
National Fire Protection Association - NFPA 70: National Electrical Code, 2023 Edition
PSI Exams - TDLR Electrician Exam Instructions
International Association of Electrical Inspectors - NEC 2026 Significant Code Changes