Article-by-article NEC code tests updated for the 2026 National Electrical Code edition.
The National Electrical Code (NFPA 70) is the rulebook for all electrical installations in the United States. It is published by the National Fire Protection Association (NFPA) and updated every three years. The current edition is NEC 2026. Most states adopt the NEC as law — meaning any electrical work that violates the NEC is an illegal installation once your state has adopted that edition.
The NEC does not cover everything (utility company work and some industrial equipment are separate), but for residential, commercial, and most industrial electrical work, it is the primary standard. Every electrician licensing exam in the US is based on the NEC.
Understanding the NEC structure helps you find answers faster on an open-book exam:
Exam tip: Learn the NEC index — look up by keyword, not by article number. "Grounding electrode conductor" → index → Art. 250 page. This is how fast test takers find answers.
NEC 2020 is the edition several state licensing boards were still testing as of 2026 — some states lag a full cycle or two behind the newest published NEC. If your state board has not confirmed a newer adoption date, these tests match what you will likely see on exam day.
NEC 2023 is the edition most state licensing boards have adopted as of 2026. If you have not confirmed your state's exact edition yet, this is the safest default to study.
NEC 2026 is the newest published edition. Tests for this edition are in development and will be added here as state boards begin adopting it.
In the meantime, our NEC Practice Tests category may already have 2026-updated content — a good place to check if your state has adopted the newest edition.
These are the major NEC articles and what each one governs. Use this as a study roadmap — start with the articles your exam tests most, then fill in the rest.
| Article | Topic | Key Rules |
|---|---|---|
| 100 | Definitions | Feeder, branch circuit, OCPD, dwelling unit, accessible, identified |
| 110 | General Requirements | Working clearances, interrupting ratings, equipment approval |
| 200 | Use and ID of Grounded Conductors | White/gray insulation, terminal identification |
| 210 | Branch Circuits | Circuit ratings, GFCI, AFCI, outlet spacing, small appliance circuits |
| 215 | Feeders | Feeder conductor sizing and OCPD |
| 220 | Branch/Feeder/Service Calculations | Dwelling unit loads, demand factors, service sizing |
| 225 | Outside Branch Circuits and Feeders | Overhead and underground conductors outside a building |
| 230 | Services | Service entrance, main disconnect, clearances, number of services |
| 240 | Overcurrent Protection | Fuses and breakers — sizing, location, accessibility |
| 250 | Grounding and Bonding | Electrode system, GEC sizing, EGC, bonding jumpers |
| 300 | Wiring Methods — General | Clearances, protection, underground, raceways, fill |
| 310 | Conductors for General Wiring | Ampacity, derate rules, insulation types, Table 310.12 |
| 312 | Cabinets, Cutout Boxes, Meter Sockets | Wire bending space, installation requirements |
| 314 | Outlet, Junction, Pull Boxes | Box fill calculations, covers, accessibility |
| 330–398 | Wiring Methods (Specific) | NM cable (330), MC cable (330), EMT (358), IMC (342), RMC (344), FMC (348), wireways (376) |
| 400 | Flexible Cords and Cables | Permitted uses, prohibited uses, cord types |
| 404 | Switches | Disconnecting means, snap switches, ratings |
| 406 | Receptacles | Ratings, configurations, tamper-resistant, GFCI, AFCI, WR |
| 410 | Luminaires (Light Fixtures) | Installation, clearances, damp/wet locations, recessed fixtures |
| 430 | Motors | Conductor sizing, OCPD, overloads, disconnects, controllers |
| 440 | HVAC Equipment | Air conditioning and refrigeration equipment — FLA, branch circuits |
| 445 | Generators | Location, OCPD, grounding, portable vs. permanently installed |
| 450 | Transformers | Installation, OCPD, clearances, vaults |
| 500–516 | Hazardous Locations | Class I/II/III, Division 1/2, Zone 0/1/2, approved equipment |
| 517 | Health Care Facilities | Patient care areas, essential electrical systems, isolated power |
| 625 | Electric Vehicle Charging | EV outlet requirements, EVSE, bidirectional charging (new in 2026) |
| 680 | Swimming Pools and Similar | Bonding, GFCI, equipotential bonding grid, lighting clearances |
| 700–702 | Emergency and Standby Systems | When required, wiring methods, transfer equipment, testing |
| 706 | Energy Storage Systems | Battery systems, solar+storage, disconnecting, ventilation (major NEC 2026 expansion) |
| 800+ | Communications | Telephone, broadband, coax — Chapter 8 stands alone |
Check your state licensing board website. As of 2026, many states are on NEC 2023. Some are beginning to adopt NEC 2026. Our tests are tagged by NEC edition so you can filter to the right one.
For most state electrician licensing exams, yes. You can bring your codebook. But you need to be fast — there is no time to read articles from scratch during the exam. Know which article to go to, then use the book to confirm the exact rule.
Most people struggle with Article 220 (load calculations) and Article 430 (motors) because they require multiple steps and correct table lookups. Practice these articles the most. Article 250 (grounding) is also heavily tested and confusing at first — read it slowly and work through examples.
Chapters 5, 6, and 7 cover special situations and they override the general rules in Chapters 1–4. For example, the rules for hazardous locations (Art. 500) override the normal wiring method rules in Chapter 3 for those locations. This "override" structure is an important concept the exam tests.
Key formulas · NEC articles · Ampacity tables · Exam tips
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