Vertiv VA5U21A0 Switched Rack Transfer Switch PDU with Outlet-Level Monitoring
Overview
The Vertiv VA5U21A0 is a 0U single-phase switched rack PDU designed for data centers, server rooms, and high-density equipment racks where you need remote per-outlet power switching combined with real-time current, voltage, and power metering. It accepts a C20 input at 100–120V / 50–60Hz and delivers up to 16A or 20A across six outlets — a mix of C13 and C19 couplers — so you can serve both standard servers and high-draw devices from a single horizontal-mount unit. If you manage remote or edge sites where physically cycling a hung server costs a truck roll, the VA5U21A0 pays for itself quickly.
This unit sits in Vertiv's rack power distribution line alongside their broader rack PDU catalog, but the VA5U21A0 specifically targets environments that need both switching control and granular metering without stepping up to a full managed PDU platform.
Key Features
- Switched Outlet Control: Individual outlet switching means you can remotely reboot a specific server, NAS, or network appliance without cutting power to the entire rack — critical for network switches or storage arrays that share a rail with always-on gear.
- Mixed C13 / C19 Outlet Configuration: The six-outlet layout supports both standard C13 (most 1U servers, patch panels, smaller appliances) and higher-current C19 devices (dense blade chassis, high-wattage GPUs) from a single PDU, reducing the number of power strips you need to manage per rack.
- LCD Display with Current, Voltage, and Power Metering: The front-panel LCD gives you at-a-glance load readings without needing to log into the management interface — useful during commissioning or when a technician is physically in the row. Monitoring current, voltage, and true power (wattage) lets you track actual load versus nameplate capacity, which matters when rack densities climb.
- C20 Input Plug on a 3-Meter Cord: The 3m (approximately 10 ft) cable run gives you enough reach from a floor-mount UPS or branch circuit PDU to the 0U position along the rear vertical rail without extension cords — a clean install on standard 42U or 45U cabinets.
- SNMP v1/v2c/v3 with Full Enterprise Protocol Stack: SNMP v3 with HTTPS, SSH, RADIUS, TACACS+, LDAP, and Syslog means this PDU integrates into existing enterprise NMS/DCIM platforms without forcing a parallel management tool. Modbus TCP support extends compatibility to building management systems (BMS) and SCADA environments common in industrial or colocation deployments.
- IPv4/IPv6 Dual-Stack Networking: Native IPv6 support future-proofs integration into networks that are mid-transition away from IPv4-only addressing — no NAT workarounds needed in IPv6-native data center segments.
- DHCP + NTP for Zero-Touch Provisioning: DHCP auto-addressing and NTP time synchronization simplify bulk deployments. When you're racking 20 units in a new cage, not having to manually configure IP addresses on each PDU saves meaningful setup time and reduces addressing errors.
- Single USB and Serial Port: The USB and RS-232 serial ports (1 each) provide local console access for initial configuration or recovery, eliminating dependency on network connectivity during first-boot setup or after a misconfigured network change locks you out.
- 0U Horizontal Mounting: Zero-U form factor mounts horizontally in 1U of rack space, keeping the full vertical rail open for revenue-generating compute. Pair it with a compatible open-frame or enclosed rack cabinet — the horizontal mount suits mid-depth or shallow racks where vertical 0U mounting isn't practical.
Integration and Compatibility
The VA5U21A0 speaks the protocols that matter in managed data center environments: SNMP v1/v2c/v3 for NMS polling and traps, Modbus TCP for BMS integration, RADIUS and TACACS+ for centralized authentication, and Syslog for event forwarding to your SIEM. LDAP/Active Directory integration means you're not managing a separate local user database on each PDU — permissions follow your existing directory structure. HTTP/HTTPS and SSH round out the access methods, and the unit supports both IPv4 and IPv6 networking natively.
The C20 input plug is compatible with standard C19/C20 power whips from floor UPS systems (APC, Vertiv/Liebert, Eaton) and branch-circuit PDUs. Outlet types — C13 for 1U/2U servers and C19 for high-current loads — cover the vast majority of rack equipment without adapters.
Frequently Asked Questions
Q: What is the input voltage and frequency range for the VA5U21A0?
A: The VA5U21A0 operates on 100–120V single-phase AC at 50 or 60 Hz, making it suited for North American and compatible international deployments on standard branch circuits.
Q: What outlet types does the VA5U21A0 provide?
A: It provides six outlets in a mix of C13 and C19 couplers. C13 outlets serve the majority of 1U/2U servers and networking gear; C19 outlets accommodate higher-current devices such as blade chassis or high-density compute nodes.
Q: Can the VA5U21A0 be managed via SNMP?
A: Yes. The VA5U21A0 supports SNMP v1, v2c, and v3, allowing it to integrate with virtually any enterprise network management system (NMS) or data center infrastructure management (DCIM) platform that supports SNMP polling and traps.
Q: Does the VA5U21A0 support remote outlet switching?
A: Yes — this is a switched PDU with per-outlet control. Individual outlets can be powered on, off, or cycled remotely through the network management interface, enabling remote server reboots without physical access to the rack.
Q: What is the mounting orientation for the VA5U21A0?
A: The VA5U21A0 is a 0U unit designed for horizontal mounting, occupying 1U of rack space. It ships with a 3-meter input cord for connection to a branch circuit or UPS output.
Q: Does the VA5U21A0 support TACACS+ and RADIUS for authentication?
A: Yes. Both TACACS+ and RADIUS are supported, enabling centralized authentication and role-based access control through your existing AAA infrastructure — no need to maintain local user accounts on each PDU independently.
The VA5U21A0 hits the right balance for managed colocation and enterprise edge deployments: you get switched outlet control and real metering in a 0U horizontal form factor, without the overhead of a full intelligent PDU platform. The SNMP v3 support combined with RADIUS and TACACS+ is the spec I always flag first — in any environment with a compliance posture, you need authenticated, encrypted management access to your power layer, and the VA5U21A0 delivers that out of the box.
Technical Highlights:
- SNMP v1/v2c/v3 + Modbus TCP: Covers both IT (NMS/DCIM) and OT (BMS/SCADA) management planes from a single unit — reduces the number of integration projects needed when a data center shares a building management system with facilities.
- Mixed C13/C19 Outlets (6 total): Eliminates the need for C19-to-C13 adapters on high-draw devices while still serving standard 1U servers — a practical advantage in dense mixed-load racks where outlet type mismatches are a common cable-management headache.
- 100–120V / 50–60Hz Input via C20: The C20 input plug mates directly with standard C19 whips from APC, Eaton, and Vertiv/Liebert UPS systems — no custom power cords, no adapters, clean integration into existing power distribution infrastructure.
Deployment Considerations:
- The 3-meter cord is generous for most cabinet depths, but verify your specific rack row layout before ordering — if the UPS is floor-mounted more than 8–9 feet from the PDU mount point, you may need an extension whip.
- This unit is rated for 100–120V only. If your data center runs 208V or 240V circuits — common in newer high-density builds — this PDU is not compatible; you'll need a 208V variant from the same Vertiv line.
This PDU is the right fit for managed colocation cages, enterprise branch server rooms, and edge deployments where remote hands are expensive and you need reliable outlet-level reboot capability plus SNMP integration into an existing NMS — without paying for features you won't use.
