The HP D4921A (D4921A - HP Redundant Power Supply for NetServer) is a Power Supplies component engineered for sustained enterprise-class workloads. This part addresses common procurement scenarios where exact-match replacement, capacity expansion, or new-build deployment is required. Technical specifications include features of Redundant. Common deployment scenarios include enterprise data-center, server-room, and managed-service-provider environments where matched-OEM-part procurement is required for warranty and compliance continuity. Pro Disk Network supplies the D4921A to US business buyers. Stocked units ship same-day on in-stock orders placed before 3pm ET. Pro Disk Network applies a 90-day functional warranty. Free US ground shipping on orders over $150; same-day expedited (UPS Next Day Air, FedEx Priority) available at checkout.
The D4921A is a HP power supplies component with features Redundant. Pricing on the D4921A is quote-based — email sales@prodisknetwork.com or use our live chat for a quote within one business day.
The D4921A is a HP power supplies part. Email sales@prodisknetwork.com with your system make, model, and serial number - we will confirm compatibility and ship same-day if in stock.
How fast does the D4921A ship?
Pro Disk Network dispatches the D4921A same-day on orders confirmed before 3 pm ET. Multi-pallet projects requiring crating ship within 2 business days. International shipping (Canada, Mexico, EU, APAC) takes 3-7 business days via DHL Express or FedEx International Priority.
The D4921A is deployed by US enterprises, MSPs, government, and education customers across multiple infrastructure scenarios. Below are the most common deployment patterns Pro Disk Network sees in real-world orders.
Branch UPS — Office or remote site UPS. 1500–3000 VA covers most server-rack mini-deployments with 5–15 minute runtime.
Datacenter UPS Module — Online double-conversion UPS for production server rooms. Match VA rating to total connected load + 30% headroom.
Telco / Battery Backup — DC-powered batteries for telco-class equipment, ISP CPE, and outdoor cabinets. Confirm voltage (-48 V vs +12/24 V).
What is the D4921A?
The D4921A is a HP server power supply unit with features Redundant, manufactured by HP. Pro Disk Network ships this part new and certified-refurbished from our US warehouse with same-day dispatch on orders placed before 3 PM ET, backed by a 30-day return guarantee.
Pros & Cons of D4921A
Pros
Lower cost than OEM channel pricing
Matched-pair option for dual-PSU redundancy
Cons
Wattage headroom should be sized at 70-80% sustained load
Cable harness sold separately on certain chassis
OEM warranty does not transfer with refurbished units
Frequently Asked Questions about D4921A
Is the D4921A a genuine HP part?
Yes. Pro Disk Network sources every D4921A as factory-original HP inventory. New units arrive sealed in OEM packaging; refurbished units are pulled from decommissioned HP servers, surface-tested, and re-warranted by Pro Disk Network for 90 days.
Will the D4921A fit my system?
The D4921A is a HP power supplies part. Email sales@prodisknetwork.com with your system make, model, and serial number - we will confirm compatibility and ship same-day if in stock.
How fast does the D4921A ship?
Pro Disk Network dispatches the D4921A same-day on orders confirmed before 3 pm ET. Multi-pallet projects requiring crating ship within 2 business days. International shipping (Canada, Mexico, EU, APAC) takes 3-7 business days via DHL Express or FedEx International Priority.
What is the warranty on the D4921A?
New D4921A units carry the full HP manufacturer warranty (typically 1 to 5 years depending on product line). Refurbished and bulk-OEM units include a Pro Disk Network advance-replacement warranty (90 days refurbished). DOA replacement is free within 30 days of receipt.
Do you offer bulk pricing for the D4921A?
Email sales@prodisknetwork.com with the quantity and target ship date for a quote within one business day.
PSU Sizing: Connected Load, Efficiency Curves, and N+1 Redundancy
For racks with shared PDUs, plan PDU capacity at 80% of breaker rating, not 100%. A 30A PDU should carry no more than 24A sustained. Distribute high-power chassis across multiple PDUs in dual-feed racks so a single PDU failure does not exceed the survivor's headroom.
AC Input, Phase Balancing, and Datacentre Power Best Practices
The D4921A accepts a defined AC voltage range, typically 100-240V or 200-240V for high-output server PSUs. Higher voltage = higher efficiency: a server PSU at 240V input runs 1-2% more efficient than the same PSU at 120V. In datacentres with 208V three-phase, balance loads across the three phases to avoid neutral saturation and reduce harmonic distortion on the upstream UPS.