Per-rack power is climbing, and the couplers you order today decide how many GPU nodes you can actually light up. A practical guide to IEC 60320 power cables for ops and sourcing teams.
Ten years ago one C13 power cord spec covered almost every server. AI and accelerator racks changed that: higher-wattage PSUs, redundant feeds and 20-30kW+ per rack mean more 16A-class connections, more C19/C20 hardware and more mistakes when someone orders "server cords" without checking the inlet. The cost of a wrong cord is not the cable — it is the rack that sits dark waiting for a re-order.
| Family | Typical rating | Where you find it |
|---|---|---|
| C13 / C14 | 10A | Standard servers, switches, monitors, most networking gear |
| C15 / C16 | 10A / 16A, high-temp | Equipment with hot inlets — some UPS/inverter and appliance internals |
| C19 / C20 | 16A (up to 20A in NA use) | High-wattage PSUs, PDU input feeds, UPS units, storage arrays, accelerator nodes |
The shapes are deliberately not interchangeable: C13 is a rounded figure-8 socket, C19 is larger and D-shaped with the ground pin on the flat side. If the device inlet is C20, only a C19-family cord fits — and vice versa. When in doubt, read the inlet marking or the manual before you order.
Both belong to the 16A family, so people use the names loosely — but they are different halves of the coupler. On the PDU or UPS input and on high-current device inlets you typically see the C20 socket; the matching cord ends in the C19 connector. Our C19 power cords cover that high-current job in US (NEMA 5-15P), EU (CEE 7/7), UK (BS 1363) and AU plug variants — same IEC connector worldwide, wall plug chosen for the destination market.
A rack PDU usually mixes C13 and C19 outlets: C13 for the standard fleet, C19 for the heavy lanes. When a high-current outlet would otherwise sit half-used, a C19/C20-to-dual-C13 splitter can feed two 10A-class devices from one branch — useful for dual-PSU servers with modest PSUs. Two cautions: add the nameplate currents before plugging anything in, and keep critical equipment on dedicated or redundant paths. Splitting is a capacity tool, not a licence to ignore branch ratings.
Longer is not better — every extra metre adds resistance and clutter. Measure the actual path from PDU outlet to PSU inlet, add a service loop, and order that length. Always follow your local electrical code for cord rating and derating.
Related reading: C19 vs C13 power cords — when the PDU needs the heavier coupler, and server rack cable management for ops teams.
Stock up from our C13 power cords, C19 power cords and C20 power cords, bundle them with a rack starter combo and a 1U cable management rack, or send us your BOM — we quote plug, length, gauge and certification together.
C13/C14 couplers are the standard 10A IEC 60320 type found on most servers, switches and monitors. C19/C20 is the heavier 16A family (commonly used at up to 20A in North America) for high-current equipment such as high-wattage power supplies, UPS units, storage arrays and rack PDU input feeds. C20 is the high-current appliance inlet on the device, and it is physically different from C14 — you cannot mix the two.
Check the PSU input rating on the nameplate or manual. Standard servers drawing 10A or less at line voltage keep using C13/C14. High-wattage PSUs that draw more than 10A per input — common on accelerator and GPU nodes — normally use the C19/C20 family. The two inlet shapes are not interchangeable, so match the cord to the inlet you actually have.
A high-current PDU outlet can feed two 10A-class devices through a C19/C20-to-dual-C13 splitter, but only if the splitter and the PDU branch are rated for the combined load. Never assume headroom — add up the nameplate currents first. For critical equipment, dedicated or redundant power paths are the safer design.