The National Electrical Code (NEC), also known as NFPA 70, is organized into multiple chapters, each containing various articles that cover specific aspects of electrical installations and safety. Here is an overview of the main structure of the 2023 NEC:

Chapter 1: General

• Article 90: Introduction
• Article 100: Definitions
• Article 110: Requirements for Electrical Installations

Chapter 2: Wiring and Protection

• Article 200: Use and Identification of Grounded Conductors
• Article 210: Branch Circuits
• Article 215: Feeders
• Article 220: Branch-Circuit, Feeder, and Service Calculations
• Article 225: Outside Branch Circuits and Feeders
• Article 230: Services
• Article 240: Overcurrent Protection
• Article 250: Grounding and Bonding

Chapter 3: Wiring Methods and Materials

• Article 300: General Requirements for Wiring Methods and Materials
• Article 310: Conductors for General Wiring
• Article 312: Cabinets, Cutout Boxes, and Meter Socket Enclosures
• Article 314: Outlet, Device, Pull, and Junction Boxes; Conduit Bodies
• Article 320 to 399: Specific Wiring Methods (e.g., Armored Cable, Nonmetallic-Sheathed Cable)

Chapter 4: Equipment for General Use

• Article 400: Flexible Cords and Cables
• Article 402: General Purpose Conductors
• Article 404: Switches
• Article 406: Receptacles, Cord Connectors, and Attachment Plugs (Caps)
• Article 408: Switchboards and Panelboards
• Article 410: Luminaires (Lighting Fixtures), Lampholders, and Lamps

Chapter 5: Special Occupancies

• Article 500: Hazardous (Classified) Locations
• Article 501 to 516: Specific Hazardous Locations (e.g., Class I, II, and III locations)
• Article 517: Health Care Facilities
• Article 518: Assembly Occupancies

Chapter 6: Special Equipment

• Article 600: Electric Signs and Outline Lighting
• Article 610: Cranes and Hoists
• Article 620: Elevators, Dumbwaiters, Escalators, Moving Walks, Wheelchair Lifts, and Stairway Chairlifts
• Article 625: Electric Vehicle Charging Systems

Chapter 7: Special Conditions

• Article 700: Emergency Systems
• Article 701: Legally Required Standby Systems
• Article 702: Optional Standby Systems
• Article 705: Interconnected Electric Power Production Sources

Chapter 8: Communications Systems

• Article 800: General Requirements for Communications Systems
• Article 810: Radio and Television Equipment
• Article 820: Community Antenna Television and Radio Distribution Systems

Chapter 9: Tables

• Contains tables for conduit and tubing fill, conductor and cable properties, voltage drop, and more.

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The National Electrical Code (NEC) Handbook not only includes the primary articles and chapters but also features additional resources at the back of the book. These resources provide further guidance, supplemental information, and tools that enhance the understanding and application of the NEC. Here is an overview of what you might find at the back of the NEC Handbook:

Annexes: These provide explanatory material, examples, and additional guidelines.

• Annex A: Product Safety Standards
• Annex B: Application Information for Ampacity Calculation
• Annex C: Conduit and Tubing Fill Tables
• Annex D: Examples of Wiring Calculations
• Annex E: Types of Construction
• Annex F: Availability and Reliability for Critical Operations Power Systems; and Development and Implementation of Functional Performance Tests (FPTs) for Critical Operations Power Systems (COPS)
• Annex G: Supervisory Control and Data Acquisition (SCADA) Systems
• Annex H: Administration and Enforcement
• Annex I: Recommended Tightening Torque Tables from UL Standard 486A-486B
• Annex J: ADA Standards for Accessible Design

Index: An extensive index to quickly find specific topics, terms, and articles.

Illustrations and Diagrams: Visual aids that help clarify complex installations and code requirements.

Tables: Numerous tables that provide necessary data such as conductor ampacities, conduit fill capacities, voltage drop calculations, and more.

Glossary: Definitions of key terms used throughout the code.

These additional resources are designed to help professionals better understand and apply the NEC’s requirements, ensuring safe and code-compliant electrical installations.

For more detailed information and to explore the articles in depth, you can refer to the NFPA’s official resources or the NEC Handbook which provides the full code along with expert commentary.