Rack PDU Buying Guide: Basic, Metered, Switched & ATS

A basic PDU is, per every manufacturer's own description of the class, a power strip built for a rack: it distributes one input circuit to several outlets with no monitoring and no remote control. It is the cheapest class and the one with the fewest things that can fail electronically.

A metered PDU adds a display or remote readout of the load passing through it - APC and CyberPower both describe this specifically as visibility into current draw, not control over it. You can see what is plugged in is drawing; you cannot turn any of it off remotely.

A switched PDU adds outlet-level remote control - the manufacturer's own stated capability is that individual outlets can be turned on and off over the network, which is how a switched PDU power-cycles a hung server without a trip to the rack. That is the maker's description of what the product does, not a use case we are recommending for your setup.

An ATS (automatic transfer switch) PDU has two power inputs, typically fed from separate circuits or separate UPS units, and automatically switches the load to whichever input is live if the other fails - again, the manufacturer's own stated behaviour for the class. It is the most expensive of the four and the only one that addresses a single-circuit failure rather than just monitoring or control.

This is what fits what, sourced to the published NEMA and IEC standards - never what you should install. A PDU's input plug and its outlets are frequently different connector types, and getting that pairing wrong is the most common expensive mistake in this category.

NEMA 5-15P is the ordinary household plug shape, rated 15A. NEMA 5-20P is a related but mechanically different plug rated 20A - the standard's own dimensional specification rotates one blade 90 degrees specifically so a 5-20P plug does not fit a receptacle that is only rated for 15A. The reverse works: a 5-15P plug fits a 5-20R receptacle, because the standard designed the 20A receptacle with a T-shaped slot that accepts both. That asymmetry is the standard's own design, not a workaround.

Twist-lock plugs (the L-series - L5-20P, L5-30P, L6-20P, L6-30P) are a separate mechanical family again, sized differently from the straight-blade 5-series and from each other by amperage class - the published standard groups 5-15/5-20 as one physical envelope, L5-20/L6-20 as a second, and L5-30/L6-30 as a third, distinct size. None of the three interchange.

On the output side, IEC C13 (rated 10A) and C19 (rated 16A) are physically different sizes - the standard's own pin spacing is 14mm horizontal on a C13/C14 pair versus 13mm horizontal but 8mm vertical on a C19/C20 pair - and the standard states plainly that connectors are dimensioned so a lower-rated one cannot be forced into a higher-rated inlet's mate. A C13 server power cord will not seat in a C20 inlet, and a C19 cord will not seat in a C14 inlet.

None of this is guidance about your circuit or your wiring. It is what the standard says fits what - check the exact input plug and outlet types stated on the PDU listing itself against what your equipment's own cords require, and if the question is whether your circuit can supply what a given plug needs, that question goes to a licensed electrician.

Basic PDUs in stock (9)

Metered PDUs in stock (11)

Switched PDUs in stock (7)

ATS PDUs in stock (17)

Where to go next

Basic, metered and switched each have their own page with the live price step and a closer look at that class · The rack hub covers the enclosure the PDU mounts in · UPS buying guide and UPS for a server rack cover the VA-vs-watts arithmetic already, not repeated here · Rack disk shelves and used servers are the equipment most often plugged into a PDU like this.

Frequently asked questions

Sources

Specification claims on this page were checked against the pages below on 4 August 2026. Where a widely-repeated figure did not survive that check, we report what the source says now and say so in the text rather than repeating the familiar number.

1. APC (Schneider Electric) - Rack PDU, Switched, Zero U, 20A, 120V, (24) 5-20 - Product Data Sheet (AP7930, discontinued) (se.com, 2026-09-13)
   Used for: APC's own published figures for this specific, discontinued PDU: "Input current limits: 20 A" and "Line Rated Current: 16 A" - both quoted verbatim from the datasheet. Also "Input Connection Type: NEMA L5-20P" and "Number of power socket outlets: 24 NEMA 5-20R," the exact plug and outlet facts for this model.
2. APC (Schneider Electric) - APC NetShelter Switched Rack PDU, 0U, 20A, 100-120V, 24 NEMA 5-20R outlets - Product Data Sheet (AP8930, current stock) (se.com, 2026-09-13)
   Used for: The same two figures on APC's CURRENTLY SOLD replacement model: "Input current limits: 20 A" and "Line Rated Current: 16 A" - confirming the pattern is not specific to one discontinued part number. Also "Product availability: Stock - Normally stocked in distribution facility," confirming this model is not discontinued.
3. Wikipedia, citing ANSI/NEMA WD 6-2016 - NEMA connector (en.wikipedia.org, 2026-09-13)
   Used for: quoted verbatim: "Compared to the 5-15P plug, the 5-20P plug has the neutral blade rotated 90° and shifted..." and "The 5-20R receptacle has a T-shaped neutral hole, to accept both 5-15P and 5-20P plugs" - the mechanical basis for why a 5-15P plug fits a 5-20R receptacle but a 5-20P plug does not fit a plain 5-15R receptacle. The same rotated-blade relationship is confirmed for the NEMA 6 (240V) family between 6-15 and 6-20. The article itself cites the dimensional standard, ANSI/NEMA WD 6-2016.
4. Wikipedia, citing IEC 60320 coupler specification sheets - IEC 60320 (en.wikipedia.org, 2026-09-13)
   Used for: quoted verbatim: C13/C14 rated "Max. current (A): 10" with "Pin spacing, centres (mm): 14 (H) / 4 (V)"; C19/C20 rated "Max. current (A): 16" with "Pin spacing, centres (mm): 13 (H) / 8 (V)" - different physical pin spacing at different amperages. Also quoted verbatim, the standard's own design principle: "The shape and dimensions of appliance inlets and connectors are coordinated so that a connector with lower current rating, temperature rating, or polarization cannot be inserted into an appliance inlet that requires higher ratings."
5. ANSI/NEMA WD 6-2016 ("Wiring Devices - Dimensional Specifications") - The standard's own front matter and dimension tables (archive.org (third-party-hosted scan, not NEMA's own distribution - flagged as such), 2026-09-13)
   Used for: quoted verbatim from the standard's own text: "This standard covers dimensional requirements for plugs and receptacles rated up to 60 Ampere and 600 Volts" and its own dimension-grouping table showing 5-15/5-20 sharing one envelope size, L5-20/L6-20 sharing a second, and L5-30/L6-30 sharing a third, distinct third size - the standard's own numeric proof that these are mechanically different parts. This is a community-uploaded scan of NEMA's copyrighted standard, not a page NEMA itself publishes for free; stated as that distinction rather than presented as NEMA's own site.
6. NavePoint - NavePoint 12U 4-Post Open Frame Server Rack, Adjustable Depth with Casters (SKU 00406437) (navepoint.com, 2026-09-13)
   Used for: quoted verbatim: "This 12U open frame rack supports stationary loads up to 1320 lbs" and the spec table's own "Weight Capacity: 1320 lbs" field - a static load rating sourced to the maker's own product page for this specific model. No dynamic/rolling load figure appears on this page; none is claimed here.
7. DatacenterDisk - Live catalogue and sourcing note - rack infrastructure & PDU cluster (datacenterdisk.com, 2026-09-13)
   Used for: every price in this cluster's tables, read from our catalogue at request time. Seeded 13 September 2026: 44 PDUs across basic/metered/switched/ATS classes, 34 racks (2-post, 4-post, enclosed, wall-mount), 10 rack accessories (shelves, blanking panels, cable management). Every electrical field (plug type, amperage, outlet count/type) is extracted from the listing's own title text and is seller-claim tier unless a specific citation above upgrades it to vendor-fact; a blank field means the listing did not state it and we did not infer one. Static/dynamic load ratings were sourced for exactly one model (source #6); every other tracked rack's load rating is unverified, stated as such rather than estimated.