Understanding NEC Article 722: Cables for Power-Limited Circuits and Fault-Managed Power Circuits

NEC Article 722 consolidates the general requirements for the installation of cables used in Class 2 and Class 3 power-limited circuits, power-limited fire alarm (PLFA) circuits, and Class 4 fault-managed power circuits. This article simplifies and organizes cable-related standards, improving clarity and accommodating evolving technologies.

Scope of Article 722

This article applies to:

• Single- and multiple-conductor cables for Class 2 and Class 3 circuits.
• Power-limited fire alarm (PLFA) circuits and Class 4 fault-managed power circuits.

Intent: Consolidation enhances usability by grouping general cable requirements for power-limited systems in one article​.

Key Requirements for Cable Installations

1. General Requirements (722.1–722.10)
   • Cables must meet the requirements for installation in various settings, including plenums, ducts, and raceways.
   • Access to equipment must not be obstructed by cable installations​.
2. Listing and Marking (722.179)
   • All cables must be listed for their intended applications, including resistance to fire spread, temperature, and voltage ratings.
   • Markings must include type designation, manufacturer identification, and applicable standards​.

Specific Installation Guidelines

1. Raceway and Tray Installations (722.3)
   • Cables must comply with specific NEC articles for raceway sizing, fire protection, and environmental considerations​.
2. Fire Resistance and Plenum Cables
   • Plenum cables must exhibit low smoke production and fire resistance per NFPA 262 standards.
   • Riser cables must prevent fire spread between floors​.
3. Circuit Integrity (CI) Cables (722.24, 722.179(A)(7))
   • CI cables maintain electrical operation under fire conditions, suitable for critical safety systems.
   • Must be supported and protected to preserve integrity​.
4. Abandoned Cable Removal (722.25)
   • Unused accessible cables must be removed unless identified for future use with durable tags​.
5. Temperature Limitations and Corrosive Locations
   • Cables must be rated for temperature and environmental conditions, ensuring durability in wet, corrosive, or damp areas​.

Applications of Article 722

• Fire Alarm Systems: Ensuring cables support reliable communication and safety during emergencies.
• Power-Limited Systems: Reducing risks in low-voltage circuits for building automation and control.
• Fault-Managed Circuits: Supporting advanced applications like distributed energy systems and data networks.

Conclusion

NEC Article 722 streamlines requirements for cables used in power-limited and fault-managed systems. Its focus on safety, proper marking, and fire resistance ensures dependable performance across diverse applications.