Understanding NEC Article 645: Information Technology Equipment
NEC Article 645 provides standards for the installation, wiring, and grounding of information technology equipment (ITE) in dedicated rooms. This ensures the safety and reliability of systems used in critical business and industrial applications, from data centers to specialized IT environments.
Scope of Article 645
This article applies to:
- ITE and systems housed within an Information Technology Equipment Room.
- Wiring, grounding, and equipment used exclusively in these rooms.
Exclusions:
- Small terminals, personal computers, and remote data equipment located outside ITE rooms.
Referenced Standards:
- NFPA 75: Fire Protection of Information Technology Equipment.
- UL 60950-1: Safety for Information Technology Equipment.
Key Requirements for ITE Rooms
- Room Construction and Accessibility
- Rooms must be fire-rated and separated from other occupancies.
- Only personnel responsible for maintenance or operation of the equipment are allowed access.
- Disconnecting Means
- Approved remote disconnect controls must power off all equipment and HVAC systems during an emergency.
- Exceptions apply to critical data systems with alternative fire suppression and evacuation procedures.
- Wiring Methods
- Branch circuits under raised floors may use flexible cables, conduits, or listed raceways.
- Only cables listed for plenum or fire-rated applications are permitted in air-handling spaces.
- Grounding and Bonding
- Non-current-carrying parts must be bonded to the system’s grounding conductor.
- Signal reference structures must be bonded to prevent interference.
- Surge Protection
- Critical operations data systems require listed surge-protective devices (SPDs).
- Fire Protection
- Fire-rated walls and smoke dampers are required for HVAC systems shared with other spaces.
- Automatic fire suppression systems must be installed in rooms without dedicated HVAC.
- Marking and Nameplates
- All ITE must have nameplates with input power requirements, including voltage, frequency, and amperage.
Special Provisions
- Under Raised Floors
- Power cords, data cables, and interconnecting conductors are permitted beneath raised floors if fire suppression systems are installed.
- Abandoned cables must be removed unless they are enclosed in raceways or marked for future use.
- Critical Operations Data Systems
- Systems exempt from remote disconnect controls require engineered procedures for fire and system shutdown.
- Uninterruptible Power Supplies (UPS)
- UPS systems must disconnect the battery from its load during shutdown.
- Selective Coordination
- Overcurrent protection for critical systems must be selectively coordinated to ensure uninterrupted operation.
Applications
NEC Article 645 ensures safe electrical installations for:
- Data Centers: Critical IT systems for enterprise and cloud computing.
- Server Rooms: Equipment hubs in commercial and industrial settings.
- Specialized IT Environments: Finance, healthcare, and manufacturing data operations.
Conclusion
NEC Article 645 provides essential standards for information technology equipment rooms, focusing on fire safety, electrical reliability, and operational integrity. By adhering to these guidelines, organizations can protect valuable IT assets and ensure system uptime in critical operations.
