A rack full of servers, switches, and control hardware needs clean, organized power delivered to many outlets, and often the ability to meter and remotely switch it. A power distribution unit does that job. This guide explains what a PDU is, the difference between basic, metered, and switched types, how PDUs relate to larger floor-level distribution, and where PDUs fit in oil and gas control and server rooms.
PDU in one line: A power distribution unit (PDU) is a device that takes one or more power inputs and distributes them to multiple outlets feeding equipment - most commonly a rack-mounted strip supplying the servers, switches, and controllers in an equipment rack. PDUs range from a simple bank of outlets to intelligent units that meter current and energy per unit or per outlet and let operators switch individual outlets on and off remotely over the network.
At its simplest, a rack PDU is a high-quality power strip built for continuous data-center-style duty: an input cord or hardwired feed, internal busbars or wiring, and a row of outlets sized for the load. It may be mounted vertically down the side of a rack (zero-U) or horizontally in a rack space. Beyond the basic strip, PDUs add intelligence in tiers.
A basic PDU only distributes power with no monitoring. A metered PDU measures the current, voltage, and energy it is delivering - either for the whole unit or per outlet - so operators can watch load and avoid overloading a circuit. A switched PDU adds relays on each outlet so equipment can be powered on, off, or rebooted remotely over the network, which is invaluable for restarting a frozen device at an unmanned site. Monitored-and-switched units combine both, reporting per-outlet power and allowing per-outlet control.
The term PDU is used at more than one scale. The rack PDU described above sits inside a single rack. In larger rooms there is also a floor-standing or floor-mounted PDU - a larger cabinet that takes a bulk feed (often from a UPS or the building distribution), sometimes steps it down through a transformer, and splits it into many branch circuits that feed the individual rack PDUs. That floor-level unit is the bridge between the building's electrical distribution and the equipment racks.
Good power distribution is built for redundancy. Racks with dual-corded equipment take feeds from two independent PDUs on separate circuits (often A and B feeds from separate UPS systems), so the loss of one feed, PDU, or circuit does not drop the equipment. Metering at the PDU level lets operators balance load across circuits and plan capacity as they add hardware.
Oil and gas control rooms, server rooms, and telecom shelters run racks of SCADA servers, historians, network gear, and communications equipment, all fed through rack PDUs. Intelligent PDUs are especially useful at remote and unmanned sites: metered units let operators watch how heavily each circuit is loaded without a site visit, and switched units let them remotely reboot a hung radio, gateway, or server that would otherwise require someone to drive out and cycle its power.
Networked PDUs report per-unit or per-outlet current, voltage, power, and energy, plus alarms for overload or lost input, typically over standard IP-based management interfaces. Where a PDU exposes its data over an industrial-friendly protocol such as Modbus, a cloud SCADA such as Merobix can read those power and status points, giving operators a view of rack power draw and feed health alongside the rest of the site's data.
A basic PDU only distributes power to its outlets with no monitoring. A metered PDU measures current, voltage, and energy - for the whole unit or per outlet - so operators can track load and avoid overloading circuits. A switched PDU adds relays that let each outlet be powered on, off, or rebooted remotely over the network. Combined monitored-and-switched units both meter per outlet and allow per-outlet control.
A rack PDU is a strip mounted inside a single equipment rack that feeds that rack's devices. A floor PDU is a larger cabinet that takes a bulk feed - often from a UPS or building distribution, sometimes through a step-down transformer - and splits it into many branch circuits that supply the individual rack PDUs. The floor unit bridges the building's electrical distribution and the racks.
A switched PDU lets operators power-cycle an individual outlet remotely over the network. At an unmanned oil and gas site, that means a hung radio, gateway, or server can be rebooted from the control room instead of dispatching someone to drive out and physically cycle its power - saving a trip and restoring service faster.
This page references the protocol specifications published by the organizations below. Editions, product capabilities, and documentation change over time - confirm current requirements and specifications directly with the source.
Last reviewed: July 27, 2026. Merobix is not affiliated with, endorsed by, or sponsored by these organizations; their names are used only to identify the standards and products discussed.
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