Article 100 of the National Electrical Code (NEC) is a critical section that provides definitions for terms used throughout the code. Understanding these definitions is essential for interpreting and applying the NEC correctly. Here is a detailed overview of the key elements covered in Article 100:

Scope of Article 100

Article 100 applies to terms that are used in two or more articles within the NEC. These definitions ensure a common understanding of the terminology used throughout the code, promoting consistency and clarity.

Key Definitions in Article 100

The definitions in Article 100 are organized alphabetically and are comprehensive, covering a wide range of terms used in electrical installations. Some of the significant definitions include:

• Accessible (as applied to equipment): Capable of being reached for operation, renewal, and inspection.
• Accessible (as applied to wiring methods): Not permanently closed in by the structure or finish of the building.
• Bonding (Bonded): The permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed.
• Ground (Grounded): Connected to earth or to some conducting body that serves in place of the earth.
• Grounding Conductor, Equipment (EGC): The conductive path(s) that provides a ground-fault current path and connects normally non-current-carrying metal parts of equipment together and to the system grounded conductor or the grounding electrode conductor, or both.

Structure of Definitions

The definitions provided in Article 100 are often accompanied by informational notes that offer additional context or examples to clarify the meaning of the terms. These notes are for informational purposes only and are not enforceable as part of the code.

Special Terms and Clarifications

Certain terms have specific meanings within the context of the NEC that might differ from their common usage. For instance:

• Qualified Person: One who has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize and avoid the hazards involved.
• Service Equipment: The necessary equipment, usually consisting of a circuit breaker or switch and fuses and their accessories, connected to the load end of service conductors to a building or other structure, or an otherwise designated area, and intended to constitute the main control and cutoff of the supply.

Changes and Updates

The definitions in Article 100 are periodically reviewed and updated to reflect changes in technology, industry practices, and safety considerations. This ensures that the NEC remains relevant and effective in promoting electrical safety.

Conclusion

Article 100 is foundational to the National Electrical Code, providing essential definitions that are used throughout the code. Understanding these terms is crucial for anyone involved in electrical installations, as it ensures consistent interpretation and application of the NEC’s requirements. For detailed information and further context, referring to the NEC Handbook and other NFPA resources is highly recommended.