Rack PDU Guide: Basic, Metered, Switched and Smart PDUs Explained
Rack Power · PDUs · Server Room Infrastructure
A rack PDU (power distribution unit) is a rack-mounted power strip that takes one incoming supply, usually from a UPS or wall circuit, and distributes it to the servers, switches and storage in a rack. There are four main types: basic, metered, switched and smart (monitored). The right choice depends on how much visibility and remote control you need. Indigi Power and Cooling supplies and installs rack PDUs across Australia and is Supply Nation and ICN Gateway registered.
The PDU is easy to overlook. It sits at the back of the rack, it costs a fraction of the UPS that feeds it, and most people only think about it when they run out of outlets. Yet every watt your IT equipment uses passes through it, and choosing the wrong one can mean tripped breakers, overloaded circuits, no warning before a failure, or a technician driving to site just to power-cycle a frozen switch.
This guide explains what a PDU is, the difference between basic, metered, switched and smart PDUs, vertical versus horizontal mounting, Australian input and outlet options, and how to choose the right PDU for your server rack or data cabinet.
What is a PDU?
PDU stands for power distribution unit. In a server room or data centre, the term almost always means a rack PDU: a heavy-duty, metal-bodied power rail designed to mount inside a 19-inch server rack or network cabinet. Unlike an office power board, a rack PDU is built for continuous high loads, uses IEC or Australian outlets suited to IT equipment, includes circuit protection, and can be fed from a UPS output or a dedicated circuit.
Larger facilities also use floor-standing PDUs, which are essentially transformer and distribution cabinets that feed whole rows of racks. This guide focuses on rack PDUs, which is what most businesses need.
Types of rack PDU
Rack PDUs are grouped by how much intelligence they have. Each step up adds visibility or control, and cost.
| PDU type | What it does | Remote access | Best for |
|---|---|---|---|
| Basic (unmanaged) | Distributes power with circuit breaker protection, no monitoring | No | Small comms cabinets, low-density racks, tight budgets |
| Metered | Shows total current draw on a local display so you can avoid overloads | Some models (network metered) | Racks where load balancing and capacity planning matter |
| Switched | Turn individual outlets on, off or reboot them remotely; sequence start-up | Yes | Remote and unmanned sites, edge racks, branch offices |
| Smart / monitored | Per-outlet power metering, energy logging, alerts, environmental sensors; often switched too | Yes, with SNMP and DCIM integration | Data centres, colocation, high-density and AI racks |
For many Australian businesses, the most valuable upgrade is from basic to switched. Being able to reboot a hung router or firewall at a regional site from your desk can save a half-day call-out. Indigi stocks the Network Switched PDU, the higher-capacity 16-port 32A switched PDU and the PowerShield Navigator Smart PDU for remote per-outlet control.
Vertical (0U) vs horizontal (1U) PDUs
Vertical PDUs mount in the rear channel of the rack and take up zero rack units (0U), which keeps all your U space free for equipment. They usually carry more outlets, place each outlet close to the device it feeds and keep power cords short and tidy. They are the standard choice for full-height 42U and 45U server racks.
Horizontal PDUs mount across the rack like any other device, using 1U or 2U of space. They suit shorter wall-mount network cabinets, open frames and racks without vertical mounting channels. See our 10-outlet vertical IEC PDU (C20 input) and 10-outlet horizontal IEC PDU (C14 input) for examples of each.
PDU inputs and capacity in Australia
The input plug determines how much power a PDU can deliver. Australian supply is 230 V single-phase or 400 V three-phase, and the PDU input must match the UPS output or circuit feeding it.
| Input | Typical plug | Maximum capacity | Plan to load to (80%) |
|---|---|---|---|
| 10A single-phase | Standard AU plug or IEC C14 | 2.3 kVA | About 1.8 kVA |
| 15/16A single-phase | 15A AU plug or IEC C20 | 3.5 to 3.7 kVA | About 2.8 to 2.9 kVA |
| 32A single-phase | 32A industrial (IEC 60309) or hard-wired | 7.4 kVA | About 5.9 kVA |
| 32A three-phase | 5-pin 32A industrial | 22.2 kVA | About 17.7 kVA |
Continuous loads should be kept at or below 80% of the PDU and circuit rating. Higher-density racks, including GPU and AI servers, often need 32A single-phase or three-phase PDUs, and sometimes two of them. If you need help converting kVA to amps, see our guide to kVA vs kW and UPS sizing.
Outlet types: Australian GPO vs IEC C13 and C19
Rack PDUs in Australia come with either standard 10A Australian outlets (GPOs), IEC outlets, or a mix. IEC C13 outlets suit most servers, switches and storage; IEC C19 outlets carry up to 16A for high-draw equipment such as blade chassis, large storage arrays and GPU servers. IEC outlets are more compact, so more fit on a PDU, and locking IEC cords help prevent accidental unplugging. Australian GPOs are handy for monitors, chargers and equipment with fixed AU plugs.
How to choose a rack PDU
- Calculate your rack load in kW or amps and add headroom for growth.
- Match the input to the UPS output or circuit: 10A, 15A, 32A single-phase or three-phase.
- Count your outlets and mix of C13, C19 and AU outlets, with spare for growth.
- Choose the intelligence level: basic, metered, switched or smart, based on how often the rack is attended.
- Pick the form factor: vertical 0U for full racks, horizontal 1U for smaller cabinets.
- Plan redundancy: dual-corded servers should be fed from two PDUs on separate A and B supplies, ideally from separate UPS units.
For single-corded equipment that still needs redundancy, a rack automatic transfer switch can switch between A and B feeds. For UPS maintenance without downtime, a hot-swap or service bypass PDU, such as the MBS Plus hot-swap PDU, lets the UPS be removed while the load stays powered.
Rack PDU supply and installation across Australia
Indigi Power and Cooling supplies and installs rack PDUs, UPS systems and server rack cooling nationally from our Brisbane, Sydney and Melbourne hubs, supporting sites across QLD, NSW, ACT, VIC, SA, WA, NT and Tasmania. Our technicians can audit your existing rack power, balance loads across phases and recommend switched or smart PDUs for remote sites.
Fitting out a new rack? We can supply the PDU, UPS and cooling as one coordinated package. Contact us for a rack power quote.
Frequently asked questions
What is a PDU?
A PDU, or power distribution unit, is a rack-mounted power rail that takes one incoming supply from a UPS or circuit and distributes it to multiple servers, switches and storage devices. Rack PDUs are built for continuous high loads and include circuit protection, unlike office power boards.
What is the difference between a metered and a switched PDU?
A metered PDU displays how much current the rack is drawing so you can avoid overloads. A switched PDU adds network access so you can remotely turn individual outlets on, off or reboot them. Smart PDUs add per-outlet metering, alerts and environmental monitoring.
What is a smart PDU?
A smart PDU, also called a monitored or intelligent PDU, connects to the network and reports power use per outlet or per PDU, logs energy, sends alerts and often supports temperature and humidity sensors. Many smart PDUs are also switched, allowing remote outlet control through a web interface or SNMP.
Should I choose a vertical or horizontal PDU?
Choose a vertical 0U PDU for full-height server racks because it uses no rack space, carries more outlets and keeps cords short. Choose a horizontal 1U PDU for smaller wall-mount network cabinets or racks without vertical mounting channels.
Can I plug a PDU into a UPS?
Yes. Feeding a rack PDU from a UPS is standard practice. The PDU input plug must match a UPS output socket, and the combined load on the PDU must stay within both the PDU rating and the UPS kW rating, ideally at 80% or less.
Related services and products
- Network Switched PDU
- Navigator Smart PDU
- 10-outlet vertical IEC PDU
- Automatic transfer switches
- Server rack cooling guide
- Server room UPS systems
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Need the right PDU for your rack? Tell us your rack size, load and UPS and we will recommend the right basic, metered, switched or smart PDU. Indigi Power and Cooling is an Indigenous and Veteran-owned critical power specialist, Supply Nation and ICN Gateway registered, supporting sites Australia-wide. Contact Indigi Power and Cooling |
