Technical Reference

Locking Power Cords Reference

Nine locking systems compared: where each locks, how the latch works and releases, the published pull-out force, the PDU outlets each needs, and which to choose — every claim with its source.

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Why locking cords matter

Accidental cord disconnection is one of the most common causes of rack downtime, and one of the easiest to prevent. A locking cord needs a deliberate action to come off, so a cable-management tidy, a neighbouring cord being pulled or a technician's elbow does not drop a server.

A standard cord is not meant to hold hard. IEC 60320-1's withdrawal test asks a plain C13 connector to keep each pin against a 1.5 N gauge and to come off a full three-pin gauge at no more than 50 N. Where the makers of locking systems publish a figure, it is 120 N for the P-Lock latch (SSEMCO) and at least 200 N for V-Lock (Schurter); several makers publish none, and this guide prints none for them.

50
Release force IEC 60320-1 allows a plain C13 connector
120,200
Published retention: P-Lock (SSEMCO), V-Lock (Schurter)
9
Locking systems stocked in East Windsor, CT

Locking systems compared

Where each system locks, how the latch works and how to release it, the maker's published retention (none is estimated), the plugs and connectors we stock, and what the other side has to be. Sources at the end.

System	Locks at	Published retention	Plugs → connectors	Mechanism and release	Needs on the other side	Notes
P-Lock (SSEMCO)	PDU outlet	Up to 120 N (about 27 lbf)	C14 · C20 → C13 · C15 · C19	Two spring tabs (P-shaped clips) on the plug head click into the outlet's latch slots. Pinch both tabs and pull.	A P-Lock-ready PDU outlet: Server Technology (lockable, HDOT, HDOT Cx), Raritan PX (SecureLock-ready), Vertiv Geist (high-retention, Combination), Eaton G4 (P-Lock C13 / C19 / C39), GELU. Seats but does not lock in a plain outlet.	The most widely deployed locking plug. Raritan sells it as SecureLock; Eaton names its G4 outlets after it. Black, blue, red from stock.
P-Lite (SSEMCO)	PDU outlet	Same latch as P-Lock; no separate figure	C14 → C13	The P-Lock latch on one side of a recessed, low-profile C14 head; a fingertip reaches the single tab on a full PDU. Press the tab and pull.	The same P-Lock-ready outlets as P-Lock.	For outlets on a pitch too tight for a full-size head; slim 18 AWG SVT. Eaton's P-Lock Lite is the same idea.
S-Lock (SSEMCO)	Equipment inlet	Not published	C14 · C20 → C13 · C15 · C19	A quarter turn of the grey collar drives internal pins that pinch the inlet's pins. Turn the collar back and pull; one hand, no side clearance.	Any standard C14 or C20 inlet; the plug is a standard, non-locking plug, so the PDU does not matter.	Rated 10 / 13 / 15 A (UL), 10 A (VDE). NEMA and hospital-grade plugs to order. Not the same as Scolmore's IEC Lock.
Dual-Lock / D-Lock (SSEMCO)	Both ends	P-Lock end up to 120 N; S-Lock end not published	C14 · C20 P-Lock → C13 · C15 · C19 S-Lock	A P-Lock plug and an S-Lock connector on one cord. Pinch the plug tabs at the PDU; turn the collar back at the equipment.	A P-Lock-ready outlet at the PDU; any standard inlet at the equipment.	Two different release motions on purpose. On a plain PDU outlet it behaves as an S-Lock.
A-Lock	Equipment inlet	Not published	C14 · C20 · NEMA 5-15P · L6-20P → C13 · C15 · C19	Spring fingers inside the connector grip the inlet pins as it is pushed on. Pinch the two red tabs and pull.	Any standard C14, C16 or C20 inlet; nothing on the PDU side matters.	The first universal locking connector; also met as WS-Lock or "auto-lock" (Well Shin). Not an APC system — APC's locking outlets take V-Lock.
V-Lock (Schurter)	Both ends	At least 200 N (about 45 lbf)	C14 · C20 → C13 · C19	A yellow spring latch on the plug and on the connector clicks into the notch of a V-Lock outlet or inlet. Press the yellow latch and pull.	A V-Lock (notched) outlet — APC AP8000-series Rack PDU 2G, Panduit SmartZone G5 — and, for the equipment end, a V-Lock inlet. Seats but does not lock anywhere else.	Schurter's system; APC's own locking cord kits (AP8702S, AP8704S) are V-Lock. The yellow is the maker's marking, not a colour option.
Z-Lock+ (Zonit, built by World Cord Sets)	Both ends	Not published	C14 · C20 → C13 · C15 · C19 · C21	At the PDU a low-profile locking nut, tightened after the plug is seated, clamps the plug in the outlet; at the equipment a spring latch inside the connector grips the inlet, with a seating line on the shell. Back the nut off to free the plug; slide the shell back to free the connector.	Nothing: any standard C13 / C19 outlet and any standard C14 / C20 inlet.	The current Zonit Z-Lock (Z-Lock Plus, ZLP on our part numbers), built on our line in East Windsor; two coloured ID rings per end. The answer for both ends on a plain PDU.
Z-Lock (Zonit, end of life)	Both ends	Not published	C14 · C20 → C13 · C15 · C19	The cords we stock carry Well Shin's locking plug and auto-locking connector: a red slider at each end. Pull the slider back and pull. Zonit's later zC14 plug used a knurled nut instead (loosen it to release).	Nothing: standard outlets and inlets.	Remaining stock only; Z-Lock+ replaces it and locks into the same hardware. It never needed a special Zonit PDU.
IEC Lock (Scolmore)	Equipment inlet	Over 100 N (about 22 lbf) — datasheet for an IEC Lock-connector cord	C14 → C13	A latch inside the C13 connector grips the earth pin of the inlet. Pull the red tab on top of the connector back and withdraw it.	Any standard C14 inlet; the plug is a standard C14.	Built here on LSZH (low-smoke zero-halogen) cordage, 10 A 250 V, for rooms where a cable fire must not fill the space with acid smoke.

Which system to choose

Start from the PDU, because the plug-side locks are the ones that depend on it. When the PDU is unknown, mixed or plain, lock the equipment end instead — those connectors grip any standard inlet.

Situation	Choose	Why
Server Technology, Raritan, Vertiv Geist, Eaton G4 or GELU PDUs; lock the PDU end	P-Lock — P-Lite where outlets are too close for a full head	Those outlets carry the latch slots the P-Lock tabs click into (each maker says so; see the sources).
The same PDUs, and the equipment must stay plugged too	Dual-Lock	A P-Lock plug for the outlet, an S-Lock collar for the inlet, two different releases.
APC AP8000-series or Panduit SmartZone G5 PDUs	V-Lock	Their locking outlets are Schurter's notched V-Lock; P-Lock seats there without locking, and A-Lock never had anything to do with APC.
Plain outlets, or a mixed / unknown PDU estate; the equipment must not come unplugged	A-Lock or S-Lock	Both lock onto any standard C14 or C20 inlet and ignore the PDU. Pick the release your technicians prefer: pinch (A-Lock) or twist (S-Lock).
Plain outlets and both ends must lock	Z-Lock+	The locking nut clamps any standard outlet and the connector latch grips any standard inlet; no special PDU. Remaining Z-Lock stock locks into the same hardware.
Low-smoke zero-halogen cordage is specified	IEC Lock	Our IEC Lock leads are built on LSZH cordage; the C13 grips the earth pin of any standard C14 inlet.
Hot inlets (120 °C rated equipment)	A C15 connector on P-Lock, S-Lock, A-Lock, Dual-Lock or Z-Lock+	C15 is the IEC 60320 connector rated for 120 °C inlets; the lock is whichever of those fits your PDU.
Telling A and B feeds apart from the aisle	Red and blue cords in any system	Every family here comes in red and blue for the A/B pair. (V-Lock's yellow latch is Schurter's marking, not a colour choice.)
Retrofitting cords already in the rack	Secure-Fit sleeves	A retention sleeve pushed onto a standard C14 / C20 plug or C13 / C19 connector adds grip without replacing the cord. It is a retrofit, not a latch: no maker publishes a retention figure for it.

The full matrix — every mechanism against every PDU outlet and equipment inlet type, with its sources — is the compatibility table on lockingpowercables.com.

Sources

SSEMCO — P-Lock C14 / C13 power cord: withdrawing force up to 120 N; mates SSEMCO R013SN / R013GX outlets; backward compatible with standard C13 outlets.
SSEMCO — S-Lock C14 / C13 power cord: second-generation rotary securing system, fits any standard C14 inlet, 10 / 13 / 15 A.
SSEMCO — locking solution products: P-Lock, P-Lite, S-Lock, D-Lock.
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.
Eaton — P-Lock and P-Lock Lite power cords.
P-Lock datasheet hosted by Server Technology: P-shaped clips, audible click, lockable and HDOT PDUs.
Raritan — SecureLock IEC power cables datasheet: latch slots inside every PX C13 / C19 outlet; C14 to C15 cords "with P-Lock".
Vertiv — Combination Outlet for Geist rack PDUs (2020): high-retention, P-Lock compatible.
Cables Plus USA — P-Lock locking power cables: receptacles found on ServerTech, Raritan and GELU PDUs.
Schurter — V-Lock connectors: latches into the notched inlet or outlet; pull-out force at least 200 N.
DigiKey — Schurter V-Lock power cords for the APC AP8000 PDU.
Panduit SmartZone G5 locking power cords: "G5 PDU side is also V-Lock compatible" (Panduit copy, reseller listing).
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.
Zonit — Z-Lock quick start guide (2017): red tabs at the connector; the nut-type plug is backed out, seated, then tightened a quarter to half turn.
Scolmore — IEC Lock C13 locking connector: pull the top tab back to fit and to release; any standard C14 inlet.
AMG Systems — LINECORD-IEC-LOCK datasheet: grips the equipment's earth pin; lock retention over 100 N.
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.
Signal+Power — Locking power cords for data centers (trade guide: WS-Lock / A-Lock, W-Lock, TwyLock).
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.

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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