Server Power Cord Types: How to Match C13/C14, C19/C20 and Locking IEC to Your Rack

A data center buildout stalls in one of two ways: the wrong cord type arrives for the equipment, or the right cord type arrives in the wrong quantity because nobody counted PDU branch loads. Both are avoidable. Server power cords are not a generic commodity — the IEC 60320 connector on the equipment end, the NEMA plug on the wall end, the ampere rating, and whether the coupler locks all determine whether the cord belongs in a rack or gets sent back.

This guide covers every server power cord type in use in North American data centers — C13/C14, C19/C20, and locking variants — with a selection chart, PDU matching guide, and a label-reading primer so procurement teams can order the exact cord the first time.

How Server Power Cord Standards Work

Every North American server power cord is governed by two separate standards that cover different ends of the same cord. Understanding which standard covers which end prevents most specification errors:

A single server power cord references both IEC 60320-1 (equipment end) and NEMA WD 6 (wall end). Neither standard covers the other end of the cord.

The IEC 60320 connector family uses numbered sheet designations — C13, C14, C19, C20 — where the number identifies the sheet in the standard that specifies that connector's geometry and rating. Even-numbered sheets (C14, C20) are male inlets built into equipment; odd-numbered sheets (C13, C19) are female couplers on cord ends. They are always sold and used as mating pairs.

Type 1: C13/C14 — Standard Server Cords (10A)

The C13/C14 pair is the most common server power connection in North American data centers. The C13 female coupler on the cord end mates with the C14 male inlet built into the server, network switch, rack-mount monitor, or standard PDU output receptacle. Rated at 10A/250V under IEC 60320-1 (typically 13A/125V in UL-listed North American cord sets), this pairing covers the majority of 1U and 2U server deployments where per-PSU input current stays under 10A.

When to specify C13/C14

• Equipment nameplate input amperage is ≤10A (IEC) or ≤13A (UL-rated cord)
• Standard 1U and 2U rack servers with single or dual PSUs at typical data center workloads
• Managed network switches — including PoE models, provided the total input draw is verified
• PDU output receptacles labeled C13/C14 (the most common output type on 1U and 2U PDUs)

For full specifications, pinout, and the C13/C14 ordering checklist, see our C13/C14 Power Cord Guide. ⚠️ Verify URL before publishing

Type 2: C19/C20 — High-Draw Server Cords (16A)

The C19/C20 pair is the correct IEC connector for high-draw equipment whose input current exceeds the C13/C14 ceiling. The C19 female coupler — physically larger than C13 and keyed to prevent cross-connection — mates with the C20 male inlet found on high-density blade server chassis, large UPS units above 1500VA, and high-capacity PDU inputs. Rated at 16A/250V under IEC 60320-1 (typically 20A/125V in UL-listed North American cord sets).

When to specify C19/C20

• Equipment nameplate input amperage exceeds 10A (IEC) or 13A (UL)
• Blade server enclosures with chassis PSUs — typically 16–30A input per chassis
• UPS units rated 1500VA and above — verify the input inlet on the rear panel
• PDU inputs fed from high-amperage branch circuits

For full specifications and the C19/C20 ordering checklist, see our C19/C20 IEC Connector Guide. ⚠️ Verify URL before publishing

Type 3: Locking IEC — When Pull-Out Is Not an Option

Standard C13 and C19 couplers rely on friction and connector geometry alone to stay seated. In most rack environments, that is sufficient. In high-traffic aisles, mobile deployments, or mission-critical environments where an accidental cord pull would take down a live server, locking IEC connectors add a mechanical retention tab that requires deliberate press-and-release action to disconnect.

How locking IEC connectors work

Locking C13 and C19 couplers incorporate a spring-loaded clip or retention latch that engages a notch on the C14 or C20 inlet body when fully seated. The lock is not a separate accessory — it is integrated into the coupler molding. To disconnect, the technician presses the release tab while pulling the cord. Accidental tension alone will not unseat the connector.

Locking IEC connectors are specified under IEC 60320-1, which includes provisions for retention mechanisms. The electrical ratings are identical to non-locking equivalents: 10A/250V for locking C13/C14, 16A/250V for locking C19/C20.

When to specify locking IEC cords

• High-traffic hot aisles and cold aisles — technician movement near live cords increases accidental pull risk
• Mobile rack deployments — wheeled enclosures that are repositioned periodically
• Shared colocation environments — where multiple tenants' technicians work in the same row
• Mission-critical single-PSU servers — any server without redundant power where a single cord disconnection causes downtime
• Vibration-prone environments — edge deployments, manufacturing floor racks, or transport racks

Master Selection Chart

Use the equipment nameplate ampere rating and inlet type as the primary decision inputs:

All IEC connectors governed by IEC 60320-1. UL 60320-1 listing required for North American deployments. NEC 80% continuous load rule (Article 210.19) applies to all circuit sizing.

Matching Cords to PDU Output Types

The PDU is the distribution point where cord type decisions cascade across an entire rack. Specifying the wrong cord after a PDU is installed and wired means rerouting or replacing the PDU — a far more expensive correction than getting it right on the purchase order.

A common architecture in a 42U rack: PDU input fed by a C19 cord from a 20A/208V circuit, with 24 C13/C14 output receptacles distributed across two 12-outlet branches. Each branch draws 12–14A total across six 1U servers at 2–2.5A each — within the 80% continuous load limit for the branch breaker.

How to Read a Server Power Cord Label

Every UL-listed server power cord carries a label or jacket marking that encodes the full specification. Knowing how to read it catches mismatches before installation:

• Connector designation: "C13" or "C19" printed on the coupler body or molded into the plastic identifies the IEC sheet. If it is missing, the cord is likely not UL-listed.
• Ampere rating: Printed as "10A" or "16A" (IEC) or "13A" / "20A" (UL) on the connector body or jacket. Ensure it matches or exceeds the equipment nameplate requirement.
• Voltage rating: "250V" for IEC; "125V" or "250V" for UL-rated cords depending on circuit. Verify the jacket voltage matches the supply voltage at the outlet or PDU.
• Wire gauge: Jacket markings such as "SJT 16/3" (16 AWG, 3 conductors) or "SJT 14/3" (14 AWG) indicate conductor size. 14 AWG is required for loads approaching the cord's rated maximum.
• UL mark and file number: A genuine UL-listed cord carries a UL mark on the plug body and jacket. The UL file number can be verified at UL Product iQ.

Before You Order: Five Checks

1. Equipment nameplate amperage. This is the only reliable input for cord selection. Use the nameplate figure — not the PSU wattage, not the typical idle draw from a monitoring dashboard.
2. Inlet type on the device. Visually confirm whether the server or UPS has a C14 or C20 inlet. They look similar from a distance; the size difference is obvious on close inspection or from the spec sheet.
3. PDU output receptacle type. Confirm C13 or C19 outputs on the PDU and count available outlets per branch before specifying cord quantities.
4. Locking requirement. Assess whether the deployment environment — traffic level, mobility, criticality — justifies locking couplers. If yes, specify locking C13 or C19 from the outset; retrofitting later requires cord replacement.
5. UL 60320-1 listing. For North American deployments, the assembled cord set must be UL-listed. Request the UL file number for bulk orders.

→ Browse Data Center Power Cords — C13, C19, locking IEC, UL-listed, multiple lengths and gauges ⚠️ Verify URL against Internal Link URL Map before publishing

Frequently Asked Questions

What are the different server power cord types?

North American data centers use four main server power cord types. C13/C14 cords (10A/250V IEC, 13A/125V UL) are the standard choice for most 1U and 2U rack servers, switches, and standard PDU outputs. C19/C20 cords (16A/250V IEC, 20A/125V UL) are used for high-draw servers, blade chassis, and large UPS units above 1500VA. Locking C13 and locking C19 variants add a retention clip for environments where accidental disconnection is a risk. Rack jumper cords (C13-to-C20 or C19-to-C14) bridge PDU outputs to devices where standard cord lengths or outlet positions require a short IEC-to-IEC extension.

What is the difference between C13 and C19 server power cords?

C13 and C19 are both female IEC couplers on the cord end, but they differ in ampere rating and physical size. C13 is rated 10A/250V and fits C14 inlets; C19 is rated 16A/250V and fits C20 inlets. The connectors are physically incompatible by design — a C19 cord cannot fit a C14 inlet, and a C13 cord cannot fit a C20 inlet. Specify C13/C14 for standard servers drawing under 10A input; specify C19/C20 for high-draw equipment above that threshold.

What are data center power cable types?

Data center power cables divide by the IEC 60320 connector on the equipment end (C13, C19, or locking variants) and the NEMA plug on the circuit end (NEMA 5-15P for 15A/125V circuits, NEMA 5-20P for 20A/125V, NEMA L6-30P for 30A/208V). The IEC end is governed by IEC 60320-1; the NEMA end is governed by NEMA WD 6. The assembled cord set must be UL-listed under UL 60320-1 for North American deployments. Rack jumper cords (IEC-to-IEC) have no wall plug and are used for PDU-to-device routing within the rack.

What server power cord types do Dell servers use?

Dell rack servers with standard single or dual PSUs typically use C13/C14 connections — the C13 cord end plugs into the C14 inlet on the PSU rear panel. High-density Dell PowerEdge servers with higher-wattage PSUs (1100W and above in some configurations) may use C19/C20 connections. Always verify the inlet type on the specific PSU model from Dell's product specification sheet or by inspecting the rear panel, as PSU options vary by server model and configuration.

When should I use a locking C13 power cord?

Use a locking C13 cord when accidental disconnection would cause downtime or data loss and cannot be prevented by cable management alone. Common scenarios include high-traffic hot aisles where technician movement risks cord contact, mobile rack deployments that are repositioned periodically, shared colocation environments with multiple tenants' technicians in the same row, and any single-PSU server without redundant power where one cord disconnection brings down the device. Locking C13 couplers mate with standard C14 inlets — no special inlet is required.

What is the standard server power cord in North America?

The most common server power cord in North American data centers is a C13-to-NEMA-5-15P cord set: a C13 female coupler on the equipment end rated 10A/250V (13A/125V UL) paired with a NEMA 5-15P three-prong plug on the wall or PDU end. This configuration covers the majority of 1U and 2U rack servers, managed switches, and standard PDU outputs. For higher-amperage equipment or 20A circuits, the cord steps up to C19/C20 on the equipment end and NEMA 5-20P on the circuit end.

References

1. IEC 60320-1 — Appliance Couplers for Household and Similar General Purposes — Part 1: General Requirements. International Electrotechnical Commission. iec.ch. Accessed: June 2026.
2. UL 60320-1 — Standard for Safety of Appliance Couplers — Part 1. UL. ul.com. Accessed: June 2026.
3. NEMA WD 6 — General-Purpose Wiring Devices. National Electrical Manufacturers Association. nema.org. Accessed: June 2026.
4. UL 817 — Standard for Cord Sets and Power-Supply Cords. UL. ul.com. Accessed: June 2026.
5. NFPA 70 — National Electrical Code, Article 210.19 (Branch-Circuit Conductors — Continuous Loads). National Fire Protection Association. nfpa.org. Accessed: June 2026.