Understanding NEC Article 708: Critical Operations Power Systems (COPS)

NEC Article 708 outlines stringent requirements for Critical Operations Power Systems (COPS), which ensure continuous operation of power for essential facilities and systems during emergencies. These systems are designed for facilities where power disruptions could severely impact national security, public health, or economic stability.

Scope of Article 708

This article applies to:

• Electrical systems providing power to Designated Critical Operations Areas (DCOA) in emergencies.
• Examples include police stations, fire stations, emergency management centers, and other facilities vital to public safety.

Informational Notes:

• Referenced standards like NFPA 1600 and NFPA 110 provide additional guidelines for emergency and standby power systems.
• Facilities protected by COPS must meet heightened reliability and security requirements, often exceeding those of other power systems.

Key Requirements for COPS

1. Risk Assessment and Mitigation (708.4)
   • A documented risk assessment identifies hazards (natural, accidental, and intentional) and assesses system vulnerabilities.
   • A mitigation strategy must address risks that are not covered by prescriptive NEC requirements.
2. Physical Security (708.5)
   • Systems must be accessible only to qualified personnel.
   • Risk assessments determine necessary physical security measures, including restricted access and robust equipment protection.
3. Testing and Maintenance (708.6)
   • Systems undergo testing upon installation and periodically thereafter.
   • Maintenance programs ensure reliability, with written records required for inspections, tests, and repairs.
4. Cybersecurity (708.7)
   • Systems connected to communication networks must undergo cybersecurity assessments.
   • Acceptable standards include NIST Framework, UL 2900, and ISA 62443.

Circuit Wiring and Equipment

1. Feeder and Branch Circuit Wiring (708.10)
   • Wiring methods must provide fire and physical damage protection, often requiring 2-hour fire-rated systems or encasement in 2 inches of concrete.
   • Circuits serving critical loads must remain entirely independent from non-critical wiring.
2. Identification and Marking (708.10(A))
   • Critical systems equipment, including receptacles, must be permanently marked for easy identification.
   • Receptacles connected to COPS must have illuminated faces or indicator lights unless located in standalone DCOA buildings.

Power Sources

1. On-Site Power Sources (708.20)
   • Backup power must activate immediately and operate for at least 72 hours at full load.
   • Systems include storage batteries, generators with on-site fuel supply, or fuel cell systems.
2. Transfer Equipment (708.24)
   • Transfer switches must prevent inadvertent interconnection of power sources.
   • Redundant or bypass isolation switches are required to facilitate maintenance.
3. Load Management (708.22(B))
   • Systems may include optional load shedding to prioritize COPS and emergency loads over non-essential systems.

Applications

NEC Article 708 is vital for:

• Critical Infrastructure: Facilities essential to national security and emergency response.
• Emergency Management: Systems supporting disaster response and recovery operations.
• High-Reliability Environments: Data centers and utility control facilities requiring uninterrupted power.

Conclusion

NEC Article 708 ensures that Critical Operations Power Systems deliver uninterrupted power to vital facilities during emergencies. By addressing risks, physical and cybersecurity, wiring, and maintenance, these systems enhance operational continuity and public safety.