APC by Schneider Electric APDU9961 Switched 0U Three-Phase Rack PDU
Overview
The APC by Schneider Electric APDU9961 is a switched, zero-unit, vertical three-phase rack PDU delivering 5,700W of managed AC power across 24 outlets in a high-density rack environment. Where standard rack PDUs give you power distribution with no control, this switched unit lets you cycle, sequence, and monitor individual outlets — meaning you can remotely hard-reset a hung server without dispatching a technician to the data center floor. If you're managing co-location racks, enterprise server cabinets, or high-density compute rows, that level of per-outlet control is the difference between a five-minute fix and a truck roll.
The APDU9961 occupies zero rack units by mounting vertically along the interior side rail of a standard rack enclosure, so none of your 1U, 2U, or 4U slots are consumed. That matters when a rack is fully populated and every horizontal unit is spoken for. The 1.8m input cable with a NEMA L21-20P plug gives you enough reach to connect to a standard 208V three-phase branch circuit without an extension — typical in North American data center environments running L21-20 receptacles on their PDPs or RPPs.
Explore the full APC by Schneider Electric power portfolio or browse the broader power distribution and UPS category for complementary infrastructure.
Key Features
- Per-Outlet Switched Control (24 Outlets): Each of the 24 outlets can be switched on, off, or power-cycled individually from a remote management interface — critical when a PDU is in a locked cage or unmanned remote site and you need to reboot a device without physical access. Outlet sequencing on power-up also prevents inrush current spikes from bringing multiple servers online simultaneously.
- Three-Phase 208V Input at 20A: Running three-phase at 208V allows more usable power per circuit than single-phase equivalents at the same amperage. At 20A input (NEMA L21-20P), the APDU9961 delivers up to 5,700W — enough headroom for dense 1U/2U compute rows without requiring a larger, more expensive distribution circuit.
- 5,700 VA / 5,700W Load Capacity: Unity power factor design (VA = W) means you're not derating for reactive loads. What the nameplate says is what you get to budget against actual server draw. Plan for 80% utilization — that puts your practical ceiling at ~4,560W, consistent with standard data center capacity planning best practices.
- Mixed Outlet Types — C13, C15, C19, C21: Four outlet form factors on a single PDU means you can serve standard servers (C13), high-temperature applications like switched-mode gear requiring C15, high-draw hosts needing C19, and C21-compatible devices — all without a plug adapter or secondary PDU. This is the outlet mix you want in a shared cabinet serving mixed equipment from different vendors.
- 0U Vertical Mounting: Occupying zero rack units and mounting vertically along the rail keeps your full 42U (or 48U) of rack space available for revenue-generating equipment. In high-density deployments where rack space has a hard dollar cost per U, this is meaningful. The vertical form factor also improves cable routing to outlet clusters along the rail height.
- 1.8m Input Cable (NEMA L21-20P): The 1.8m (approximately 6 ft) cable is long enough to reach a floor-mounted or overhead PDU whip in most row-based data center configurations without needing a cable extender — one less failure point and one less SKU to manage.
- Wide Frequency Acceptance (50–60 Hz): Accepts both 50Hz and 60Hz input, so this unit deploys equally in North American (60Hz) and international (50Hz) facilities without modification — useful for multinational enterprises standardizing on a single PDU model across global sites.
- RoHS Compliance + IEC 62368-1 Certification: RoHS compliance keeps this unit acceptable in environmentally regulated procurement programs. IEC 62368-1 is the current audio/video, IT, and communication equipment safety standard — its presence here signals the unit has been evaluated under a more rigorous, hazard-based framework than the older IEC 60950-1. CUL listing confirms Canadian safety compliance alongside FCC Part 15 Class A for EMI.
Integration and Compatibility
The APDU9961 is designed for data center rack infrastructure, compatible with standard EIA-310 19-inch or 23-inch rack enclosures via vertical side-rail mounting. The NEMA L21-20P input plug pairs with the three-phase L21-20R receptacles found on most North American data center PDUs (panel-mounted whips or overhead busway drops at 208V). The mixed outlet complement — C13, C15, C19, C21 — covers the IEC connector standard used across virtually all rack-mount servers, storage arrays, and networking gear from major OEMs.
For pairing with an upstream uninterruptible power supply (UPS), confirm that the UPS output circuit supports NEMA L21-20 at 20A; many three-phase UPS systems in the 10–20kVA range include compatible receptacles on their output distribution. For other rack PDU options in this current and voltage class, compare outlet counts and managed features against your specific rack head-count and remote-management requirements.
Frequently Asked Questions
Q: What input plug does the APDU9961 use, and what circuit does it require?
A: The APDU9961 uses a NEMA L21-20P input plug and requires a three-phase 208V, 20A circuit. This is a standard twist-lock plug format found on most North American data center branch circuit receptacles at 208V three-phase.
Q: How many outlets does the APDU9961 have, and what outlet types are included?
A: The APDU9961 provides 24 total AC outlets across four IEC connector types: C13, C15, C19, and C21. This mixed complement allows you to serve standard servers, high-temperature-rated devices, high-draw hosts, and C21-compatible equipment from a single PDU without adapters.
Q: Can the APDU9961 be managed remotely, and does it support per-outlet switching?
A: Yes. As a switched PDU, the APDU9961 supports per-outlet on/off/reboot control via its network management interface — enabling remote hard resets of hung devices without a physical site visit. Outlet sequencing on power-up is also supported to prevent simultaneous inrush current from multiple loads.
Q: Does the APDU9961 take up rack unit space?
A: No. The APDU9961 is a 0U (zero-unit) vertical PDU that mounts along the interior side rail of a standard rack enclosure, consuming none of your horizontal rack unit space. All 1U through 4U+ slots remain available for equipment.
Q: What safety and regulatory certifications does the APDU9961 carry?
A: The APDU9961 is certified to IEC 62368-1 (the current hazard-based IT/AV equipment safety standard), carries CUL listing for Canada, FCC Part 15 Class A for EMI compliance, and meets RoHS requirements for restricted substances.
Q: What is the maximum power capacity of the APDU9961?
A: The APDU9961 is rated at 5,700W (5,700 VA) maximum load capacity. Standard data center capacity planning practice targets 80% utilization, which puts the practical operating ceiling at approximately 4,560W.
When I spec switched PDUs for high-density compute rows, the outlet mix is often what makes or breaks a deployment — and the APDU9961 gets this right with C13, C15, C19, and C21 connectors across all 24 outlets, so you're not ordering plug adapters or a second PDU just to serve a mixed-vendor cabinet. The 5,700W capacity at 208V three-phase keeps you well within range for a fully populated 1U server row, and the 0U vertical form factor means you're not sacrificing rack space to get there.
Technical Highlights:
- Per-Outlet Switched Control: Individual outlet on/off/cycle via network management is the core value of this unit — at a co-lo cage or unmanned edge site, remote hard reset capability directly reduces truck rolls. Outlet sequencing on startup prevents simultaneous inrush from 24 loads hitting the branch circuit at once.
- 5,700W Unity Power Factor: VA equals W on this unit, so the nameplate capacity is the real capacity — no derating calculation required. Budget 80% (≈4,560W usable) against actual server draw totals and you have a clear, honest capacity ceiling.
- Four IEC Outlet Types: C13 for standard servers, C15 for higher-rated thermal applications, C19 for high-draw compute nodes, C21 for compatible high-density gear — all on one PDU. This eliminates the SKU proliferation that comes with trying to match a single-outlet-type PDU to a mixed cabinet.
Deployment Considerations:
- The NEMA L21-20P input requires a three-phase 208V/20A branch circuit — confirm your PDP or RPP has L21-20R receptacles available before ordering. Single-phase infrastructure is not compatible with this plug type.
- At 20A input, the NEC 80% continuous load rule puts your safe continuous operating ceiling at 16A (approximately 3,328W at 208V three-phase) for circuits serving continuous loads — factor this into cabinet power budgets if your servers run sustained workloads rather than peak-only bursts.
The APDU9961 is the right call for a shared enterprise cabinet or co-location deployment running mixed IEC-connector equipment on 208V three-phase infrastructure, where remote outlet control eliminates the operational cost of physical access for routine device resets.
