What Is NEC Article 725?

NEC Article 725 is part of the National Electrical Code (NEC) that covers the installation of Class 1, Class 2, and Class 3 remote-control, signaling, and power-limited circuits. It sets the general rules for wiring methods, conductor sizing, overcurrent protection, and separation from other wiring systems.

Scope and Purpose

The article ensures these control and signaling circuits are installed to prevent fire, shock, and interference hazards. It applies to applications such as industrial automation, machine control, HVAC systems, security systems, and building automation networks.

Key Requirements

• Determine circuit classification (Class 1, 2, or 3).
• Use approved wiring methods for each class.
• Provide proper overcurrent protection.
• Maintain required separation from power conductors.
• Follow listing and marking rules for cables and equipment.

Conclusion

NEC Article 725 provides the foundation for safe, code-compliant installation of control, signaling, and power-limited circuits, forming the basis for more detailed rules such as those in NEC 725.154.