Understanding the CN3K-PAC-400W-B= Power Supply

The ​​CN3K-PAC-400W-B=​​ is a 400-watt AC power supply unit (PSU) designed for Cisco Nexus 3000 series switches, such as the Nexus 3064 or 3172 models. While Cisco’s official documentation does not explicitly list this exact SKU, the naming convention aligns with Cisco’s standard PSUs for the Nexus 3000 platform. Third-party vendors like itmall.sale position it as a compatible, cost-efficient replacement or upgrade for enterprises seeking redundancy or expanded power capacity.

Technical Specifications and Design

• ​​Power Output​​: Delivers 400W with ​​90–94% efficiency​​, meeting 80 Plus Silver or Gold standards.
• ​​Input Voltage​​: Supports 100–240V AC, ideal for global deployments.
• ​​Form Factor​​: Hot-swappable front-mounted module, compatible with dual-PSU Cisco Nexus 3K chassis.
• ​​Cooling Mechanism​​: Incorporates variable-speed fans for temperature-dependent airflow management.

Core Applications in Network Infrastructure

This PSU is critical for:

1. ​​High-availability data centers​​: Provides redundant power for mission-critical Nexus switches.
2. ​​Edge computing deployments​​: Ensures stable operation in environments with fluctuating power quality.
3. ​​Hardware upgrades​​: Replaces aging or underpowered PSUs in existing Nexus 3000 setups.

Addressing Key Buyer Questions

“Is the CN3K-PAC-400W-B= compatible with all Nexus 3000 switches?”

Yes, provided the chassis supports 400W PSUs. For example, the Nexus 3172PQ requires dual 450W PSUs, making this 400W unit unsuitable. Confirm ​​switch power budgeting​​ before purchase.

“How does it compare to Cisco’s original PSUs?”

While performance metrics like efficiency are nearly identical, the [“CN3K-PAC-400W-B=” link to (https://itmall.sale/product-category/cisco/) lacks Cisco’s standard firmware integration for predictive failure analytics.

Sourcing Considerations and Risk Mitigation

itmall.sale markets this PSU as a refurbished or alternative-compatible unit. To minimize risks:

• ​​Validate thermal compatibility​​: Test airflow alignment (e.g., port-side exhaust) to prevent overheating.
• ​​Check redundancy protocols​​: Ensure graceful failover during power outages (tested <10ms switchover).
• ​​Review certifications​​: Verify UL/CE markings for regional compliance.

Final Perspective: Balancing Cost and Uptime

Power supplies like the CN3K-PAC-400W-B= highlight the hidden backbone of network reliability. While Cisco’s OEM units offer peace of mind through integrated diagnostics, third-party alternatives empower organizations to extend hardware lifecycles cost-effectively—provided they commit to rigorous pre-deployment testing. From firsthand experience, the ROI of such modules becomes evident in large-scale deployments where marginal savings compound, as long as teams prioritize vendor transparency and component traceability. For non-mission-critical environments, this PSU is a pragmatic choice; for others, it’s a gamble worth calculating.