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Locking Power Cord Comparison: Which System Is Right for Your Data Center?

P-Lock, P-Lite, S-Lock, Dual-Lock, A-Lock, V-Lock, Z-Lock+ and IEC Lock compared side by side — where each locks, the published pull-out force, the PDU outlets each needs, and a selection guide, every claim with its source.

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By World Cord Sets Engineering Team · Updated September 2026 · 8 min read

Why locking power cords matter

Uptime Institute's outage analyses put power problems at the top of the causes of significant data-center outages, with human error behind most of them — and a cord pulled during maintenance is the most ordinary human error a rack can suffer. A locking cord turns that pull into a non-event.

A standard cord is designed to come off. IEC 60320-1's withdrawal test asks a plain C13 connector to hold each pin against a 1.5 N gauge and to release from a full three-pin gauge at no more than 50 N. The locking systems below publish 120 N (P-Lock, SSEMCO) to at least 200 N (V-Lock, Schurter) where their makers publish a figure at all; the ones that publish none are marked so below, because an unsourced number is worth less than none. In a 132 kW AI rack where one cord pull can cascade through dozens of servers, the premium for a locking cord is small against a single incident.

All systems compared

SystemLocks atPublished pull-out forceColoursWhat the other side must beBest for
P-Lock (most deployed)PDU outletUp to 120 N — SSEMCOBlack, blue, red; others to orderA P-Lock-ready outlet: Server Technology, Raritan (SecureLock-ready), Vertiv Geist, Eaton G4, GELU. Seats without locking in a plain outlet.Locking the PDU end on those PDUs — the common case
P-LitePDU outletSame latch as P-Lock; no separate figureRed, blue, blackThe same P-Lock-ready outletsHigh-density PDUs where a full P-Lock head blocks its neighbour
S-LockEquipment inletNot publishedBlack; others to orderAny standard C14 / C20 inlet; the PDU does not matterCrowded inlets; a twist release with no side clearance
Dual-Lock (D-Lock)Both endsP-Lock end up to 120 N; S-Lock end not publishedBlack, red, blueA P-Lock-ready outlet at the PDU; any inlet at the equipmentBoth ends on Server Technology / Raritan / Vertiv / Eaton G4 racks
A-LockEquipment inletNot publishedBlack, red, blueAny standard C14 / C16 / C20 inlet; the PDU does not matterAny PDU, unknown or mixed; pinch-tab release
V-LockBoth endsAt least 200 N — SchurterBlack, red, blue; the yellow latch is the maker's markingA V-Lock (notched) outlet — APC AP8000-series, Panduit SmartZone G5 — and a V-Lock inlet for the equipment endAPC AP8000 and Panduit G5 racks
Z-Lock+ (both ends, any PDU)Both endsNot publishedBlack, red, blue and more, with two ID rings per endNothing special: standard outlets and inletsBoth ends locked on plain PDUs; the current Zonit Z-Lock, built by us
Z-Lock (end of life)Both endsNot publishedBlack, red, blueNothing special: standard outlets and inletsRemaining stock; Z-Lock+ replaces it
IEC LockEquipment inletOver 100 N — datasheet for an IEC Lock-connector cordBlackAny standard C14 inletC14-to-C13 leads on LSZH cordage

C15 connectors (rated for 120 °C inlets) are available on P-Lock, S-Lock, A-Lock, Dual-Lock and Z-Lock+. Every figure above is the maker's published one; where a maker publishes none, the table says so.

Every mechanism against every PDU outlet and equipment inlet type, with its sources: the compatibility table on lockingpowercables.com.

Sources

  1. SSEMCO — P-Lock C14 / C13 power cord: withdrawing force up to 120 N; mates SSEMCO R013SN / R013GX outlets; backward compatible with standard C13 outlets.
  2. SSEMCO — S-Lock C14 / C13 power cord: second-generation rotary securing system, fits any standard C14 inlet, 10 / 13 / 15 A.
  3. Eaton — Tripp Lite series P-Lock power cords brochure: P-Lock C13 / C19 / C39 outlets on G4 PDUs; the tabs click into a compatible P-Lock outlet.
  4. P-Lock datasheet hosted by Server Technology: P-shaped clips, audible click, lockable and HDOT PDUs.
  5. Raritan — SecureLock IEC power cables datasheet: latch slots inside every PX C13 / C19 outlet; C14 to C15 cords "with P-Lock".
  6. Vertiv — Combination Outlet for Geist rack PDUs (2020): high-retention, P-Lock compatible.
  7. Schurter — V-Lock connectors: latches into the notched inlet or outlet; pull-out force at least 200 N.
  8. DigiKey — Schurter V-Lock power cords for the APC AP8000 PDU.
  9. Panduit SmartZone G5 locking power cords: "G5 PDU side is also V-Lock compatible" (Panduit copy, reseller listing).
  10. Zonit — Z-LOCK PLUS announcement (May 2023): dual and single-sided C13 / 14 / 15 and C19 / 20 / 21, two coloured ID rings per endcap, standard IEC receptacles.
  11. Scolmore — IEC Lock C13 locking connector: pull the top tab back to fit and to release; any standard C14 inlet.
  12. AMG Systems — LINECORD-IEC-LOCK datasheet: grips the equipment's earth pin; lock retention over 100 N.
  13. Interpower — the IEC 60320-1 withdrawal-force test: each C13 contact holds a 1.5 N gauge; the connector must release from the three-pin gauge at no more than 50 N.
  14. lockingpowercables.com — the compatibility table: every mechanism against every outlet and inlet type, with sources.

Checked against these sources on September 21, 2026. If your PDU is not named, send us the model and we will check the outlet before you order.

Selection guide

Which system should you choose?

Start from the PDU: the plug-side locks depend on it, the equipment-side locks do not.

  • PDU is Server Technology, Raritan, Vertiv Geist, Eaton G4 or GELU: P-Lock

    Those makers build outlets with the latch slots the P-Lock tabs click into — Server Technology's lockable and HDOT outlets, every Raritan PX outlet (Raritan sells the plug as SecureLock), Vertiv Geist's high-retention and Combination outlets, Eaton G4's P-Lock C13 / C19 / C39 outlets. Up to 120 N of retention, SSEMCO's published figure. Pick P-Lite where outlets sit too close for a full-size head.

  • PDU is APC AP8000-series or Panduit SmartZone G5: V-Lock

    Their locking outlets are Schurter's notched V-Lock, and APC's own locking cord kits are V-Lock cords. The yellow latch on the plug and the connector clicks into the notch, with a pull-out force Schurter rates at 200 N or more. A P-Lock plug seats in those outlets but does not lock — and A-Lock, despite what older guides said, has nothing to do with APC.

  • Both ends must lock on a P-Lock-ready PDU: Dual-Lock

    SSEMCO's D-Lock: a P-Lock plug for the outlet and an S-Lock rotary connector for the inlet, on one cord, with two different releases so freeing one end does not free the other by reflex. Right for AI compute racks whose PDUs are Server Technology, Raritan, Vertiv or Eaton G4.

  • Both ends must lock and the PDU has plain outlets: Z-Lock+

    Zonit's Z-Lock Plus, built on our line in East Windsor. A low-profile locking nut clamps the plug in any standard C13 or C19 outlet; a spring latch in the connector grips any standard C14 or C20 inlet; two coloured ID rings per end. No special PDU, no special equipment — the answer the faceplate systems cannot give. The original Z-Lock never needed a special Zonit PDU either; the remaining stock locks into the same hardware.

  • Mixed or unknown PDUs, and the equipment must stay plugged: A-Lock or S-Lock

    Both lock the connector onto any standard C14 or C20 inlet and ignore the PDU entirely, so they are the safe choice for an estate of many PDU brands. A-Lock releases by pinching two red tabs; S-Lock by turning a grey collar a quarter turn, with no side clearance needed. Neither maker publishes a retention figure, so we print none.

  • Low-smoke zero-halogen cordage is specified: IEC Lock

    Scolmore's IEC Lock C13 grips the earth pin of any standard C14 inlet and releases by the red tab on top. Our leads are built on LSZH cordage at 10 A for equipment rooms, tunnels and ships where a cable fire must not fill the space with acid smoke.

FAQ

Frequently asked questions

Which locking power cord works with any PDU?
The ones that lock at the equipment end: A-Lock, S-Lock and IEC Lock grip any standard C14 or C20 inlet and do not care what the PDU is. For both ends on a plain PDU, Z-Lock+ locks into standard outlets and inlets with no special hardware. P-Lock, P-Lite and Dual-Lock lock only into a P-Lock-ready PDU outlet (Server Technology, Raritan SecureLock-ready, Vertiv Geist, Eaton G4, GELU); in a plain outlet they seat but do not lock.
What is the pull-out force of a locking power cord?
Only two makers publish a figure for the systems we stock: SSEMCO rates the P-Lock latch at up to 120 N (about 27 lbf), and Schurter rates V-Lock at 200 N (about 45 lbf) or more. A datasheet for a cord on Scolmore's IEC Lock connector publishes over 100 N. No figure is published for S-Lock, A-Lock, Dual-Lock's S-Lock end, Z-Lock or Z-Lock+, and we do not print one. For scale, IEC 60320-1 requires a plain C13 to release from its test gauge at no more than 50 N.
Do P-Lock cords work with APC PDUs?
They plug in and carry current, but they do not lock. APC's AP8000-series Rack PDU 2G locking outlets are Schurter V-Lock, so the cord that locks there is a V-Lock cord — APC's own locking cord kits (AP8702S, AP8704S) are V-Lock. A-Lock is not an APC system; it is the universal equipment-side connector.
What is the difference between Z-Lock and Z-Lock+?
Both are Zonit's two-ended lock for standard outlets and inlets; neither needs a special PDU. Z-Lock+ (Z-Lock Plus, ZLP on our part numbers) is the current version, built by World Cord Sets in Connecticut: a low-profile locking nut at the plug, a sliding-shell release at the connector, a seating line, two coloured ID rings per end, and C21 added to the connector range. The original Z-Lock is end of life; our remaining stock has a red slider at each end, and Zonit's later plug used a knurled nut.
What is a Dual-Lock (D-Lock) power cord?
SSEMCO's cord with a P-Lock plug at the PDU and an S-Lock rotary connector at the equipment, so both ends lock. The plug end needs a P-Lock-ready outlet, the connector end takes any standard inlet, and the two releases are deliberately different motions — pinch the tabs at the PDU, turn the collar at the equipment.
Do locking cords prevent every accidental disconnection?
They prevent the pull: every system here needs a deliberate release action — pinch, twist, press, slide or unscrew — so a snag or a tidy does not drop the load. They do not lock where the other side is not built for them: a P-Lock or V-Lock plug in an outlet without the latch slot or notch seats like an ordinary cord. Match the system to the outlet first; the compatibility table on lockingpowercables.com shows every pairing with its source.

Shop locking power cords

P-Lock, P-Lite, S-Lock, Dual-Lock, A-Lock, V-Lock, Z-Lock+ and IEC Lock from stock in Connecticut; same-day shipping on in-stock orders.

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