Vertiv Rpdu Rack Transfer Switch Switched Outlet Level Monitoring 20A 120V 1.9KW H - VA7N21A1

Vertiv VA7N21A1 Rack Transfer Switch with Switched Outlet-Level Monitoring

Overview

The Vertiv VA7N21A1 is a 0U horizontal rack PDU combining automatic transfer switch functionality with switched, outlet-level monitoring in a single 1U-friendly chassis. Rated at 20A / 120V (1.9 kW) with a NEMA L5-20P twist-lock input and six NEMA 5-20R output receptacles, the VA7N21A1 is built for data center racks, server rooms, and telecom enclosures where uptime depends on both source redundancy and granular load visibility. The unit monitors current, voltage, and power at the outlet level — meaning you know exactly which circuit is pulling what, not just aggregate draw at the inlet.

As part of the Vertiv rack PDU and power distribution line, the VA7N21A1 occupies the 0U position on the side of a standard rack, keeping all 1U and 2U slots available for active equipment. The 3-meter input cord gives enough slack to reach a dedicated 20A L5-20P circuit without extension cords or awkward routing.

Key Features

• Automatic Transfer Switch (ATS) + Switched Outlets: The VA7N21A1 combines two distinct functions — it automatically switches between two power sources if one fails, and it gives you remote on/off control of each individual NEMA 5-20R outlet. That means you can power-cycle a hung server from a browser or SNMP management console without dispatching anyone to the data floor.
• 6 Switched NEMA 5-20R Outlets on a 20A / 120V Circuit: Six independently controllable receptacles share the 20A feed. At 1.9 kW max, that's roughly 316W per outlet if loaded evenly — realistic for 1U servers or networking gear. Outlet-level switching eliminates the need for a separate remote power manager alongside the PDU.
• Outlet-Level Current, Voltage, and Power Monitoring: Most basic PDUs report inlet amperage only. The VA7N21A1 reports current, voltage, and power at each outlet — so you can catch a failing PSU drawing abnormally, enforce per-outlet load limits, and generate accurate power-consumption reports for capacity planning without guesswork.
• NEMA L5-20P Twist-Lock Input: The locking plug prevents accidental disconnection on the primary feed — a real operational hazard in dense racks where cable management is imperfect. Pair it with a dedicated 20A circuit breaker on a 5-20 circuit via an L5-20P to 5-20R adapter if needed.
• LCD Display for Local Readout: An onboard LCD gives local staff immediate visibility into load status without needing laptop access or a console cable. In loud, busy data halls where network access can be disrupted, local display matters.
• 0U Horizontal Mounting — Zero Rack Unit Consumption: The horizontal 0U form factor mounts to the side rail or dedicated 0U bracket of a standard rack, leaving every rack unit free for revenue-generating hardware. No 1U or 2U penalty for power management.
• Dual-Stack IPv4/IPv6 Network Management: The single RJ-45 Ethernet port supports both IPv4 and IPv6 — so the VA7N21A1 integrates into modern dual-stack data center networks without address-space workarounds. Access it via HTTPS for encrypted web UI or SSH for CLI management.
• Enterprise Protocol Suite — SNMP v1/v2c/v3, LDAP, RADIUS, TACACS+: SNMP v3 delivers authenticated, encrypted trap delivery to your NMS (SolarWinds, PRTG, Nagios, and similar). LDAP, RADIUS, and TACACS+ mean user authentication integrates with your existing directory infrastructure — no local password sprawl across dozens of PDUs. Syslog and SMTP cover event logging and alerting without custom integrations.
• Modbus TCP Support: Modbus TCP enables integration into BMS (building management systems) and DCIM platforms that poll Modbus registers for power data — common in larger colocation and enterprise data center environments where power readings feed upstream capacity management dashboards.
• USB and Serial Console Ports: The USB port and RS-232 serial port (RJ-45 form factor, 1x) provide out-of-band management options. Serial console is the last-resort access path when network connectivity fails — a necessary feature in any PDU that you're trusting to manage critical infrastructure.
• 3-Meter Input Cord: A 3m (approximately 10 ft) cord reaches from the rack-mounted PDU to a wall-mounted or floor-mounted power panel without strain or tight bends. Shorter cords force cable ties and stress connectors; longer cords create slack management problems. 3m is a practical middle ground for most standard rack deployments.
• Broad Protocol Support for Security: HTTPS, SSH, SNMPv3, and support for RSTP (Rapid Spanning Tree) network topology awareness mean the management plane of the VA7N21A1 is not an open attack surface. LDAP/RADIUS/TACACS+ centralize access control, so disabling a departed employee's PDU access happens in one place.

Integration and Compatibility

The VA7N21A1 connects to any rack PDU management ecosystem that speaks SNMP v1/v2c/v3 or Modbus TCP — including SolarWinds NMS, Vertiv's own Environet platform, PRTG Network Monitor, and most DCIM tools. The SNMP MIB for Vertiv Geist-series PDUs is publicly available from Vertiv for import into your NMS. LDAP integration targets Active Directory and OpenLDAP environments; RADIUS and TACACS+ cover network-centric AAA environments common in telecom and colo deployments.

For power infrastructure planning, pair the VA7N21A1 with an appropriate UPS or uninterruptible power supply upstream on each source feed — the ATS functionality is only as reliable as the two independent sources feeding it. Both feeds should originate from separate breakers on separate distribution panels, or ideally from separate utility feeds, for genuine redundancy.

The 50/60 Hz dual-frequency input accommodates both North American 60 Hz and international 50 Hz grid infrastructure, though the 100–120V nominal input voltage limits use to North American and Japanese mains voltage environments.

For facilities teams building out data center power distribution infrastructure, the VA7N21A1's Modbus TCP interface allows polling by Schneider EcoStruxure, Vertiv Environet, and similar DCIM platforms — enabling the PDU's per-outlet power data to feed into rack-level and room-level capacity dashboards automatically.

Frequently Asked Questions

Q: What input plug does the VA7N21A1 use, and what circuit do I need?

A: The VA7N21A1 uses a NEMA L5-20P twist-lock input plug and requires a dedicated 20A, 120V single-phase circuit. The twist-lock design prevents accidental disconnection. You'll need a NEMA L5-20R receptacle at the power panel or PDU feed point.

Q: Does the VA7N21A1 support SNMP v3 with encryption?

A: Yes. The VA7N21A1 supports SNMP v1, v2c, and v3. SNMPv3 includes authentication and privacy (encryption), making it the appropriate choice for secure network management environments. Syslog and SMTP alerts are also supported for event notification.

Q: Can individual outlets be switched off remotely without affecting the others?

A: Yes. Each of the six NEMA 5-20R outlets can be independently switched on or off via the web UI (HTTPS), SSH CLI, or SNMP commands. This allows remote power cycling of individual servers or devices without disrupting the rest of the load.

Q: What authentication methods does the VA7N21A1 support for user management?

A: The unit supports LDAP, RADIUS, and TACACS+ for centralized user authentication, in addition to local user accounts. This allows integration with Active Directory, FreeRADIUS, or Cisco ISE for consistent access control across your PDU fleet.

Q: Is the VA7N21A1 compatible with DCIM and BMS platforms?

A: Yes. Modbus TCP support enables polling by DCIM and building management systems that use Modbus registers for power data — including Vertiv Environet and similar platforms. SNMP v3 covers NMS tools like SolarWinds, PRTG, and Nagios.

Q: What is the maximum power capacity of the VA7N21A1?

A: The VA7N21A1 is rated at 20A / 120V, yielding a maximum of 1.9 kW (1,900W) total output. Across six outlets, that averages roughly 316W per outlet at full load — appropriate for 1U servers, networking equipment, and similar loads.

Eden Phillips

The VA7N21A1 caught my attention specifically because of the outlet-level monitoring combined with transfer switch functionality in a single 0U unit — that's a feature combination that normally requires two separate devices in a rack. Most facility managers deploying this unit are dealing with a dense rack where every U counts, and the horizontal 0U mounting keeps those units free. The 20A / 120V NEMA L5-20P input is the right spec for a dedicated branch circuit feeding a half-populated server rack or a high-density networking cabinet.

Technical Highlights:

• Outlet-Level Monitoring (Current, Voltage, Power): Monitoring at the outlet rather than just the inlet gives you per-device load data — critical for capacity planning when you're tracking watts-per-rack against facility power allocations. You can set per-outlet thresholds and get alerts before a circuit approaches its 20A limit.
• SNMP v1/v2c/v3 + Modbus TCP: SNMP v3 handles encrypted trap delivery to your NMS, while Modbus TCP opens the door to DCIM and BMS integration without a gateway appliance. Having both on a single PDU at this price tier is not universal — it positions the VA7N21A1 well above basic monitored-only units.
• LDAP / RADIUS / TACACS+ Authentication: Centralized auth means PDU access management scales with your fleet. When a technician leaves, one AD group change disables access across every VA7N21A1 in the facility — you're not chasing local passwords on individual units.

Deployment Considerations:

• The NEMA L5-20P input requires a matching L5-20R receptacle at your power panel — verify your facility's panel configuration before ordering. If you're feeding from a standard 5-20R, you'll need an adapter, which adds a potential failure point and is not recommended for a primary ATS feed.
• The 100–120V input range limits this unit to North American and Japanese mains environments. If you have racks in European or international facilities on 230V infrastructure, this model is not the right fit — Vertiv's 208/230V variants serve those deployments.

The VA7N21A1 is the right specification for a colocation or enterprise data center rack where you need ATS source redundancy, remote outlet control, and per-outlet power telemetry all reporting into a central NMS via SNMPv3 — without sacrificing a single rack unit to get there.