C19 vs C20

This is the larger IEC 60320 pair. It is the usual jumper for 16 A class inlets.

Which end goes where

Into the server	The C19 coupler goes into the C20 inlet on the PSU
Into the PDU	The C20 plug goes into a C19 outlet on the PDU
C20	Inlet on a high-watt PSU, and the plug end of the jumper
C19	Coupler on the jumper, and the outlet on the PDU
Current class	16 A class. A C13–C14 jumper does not mate with a C20 inlet

When you need C13 instead

If the inlet on the PSU is C14, the cord is a C13–C14 jumper, not this pair. See C13 vs C14.

How to remember it

Same odd/even rule as C13/C14: C19 coupler into C20 inlet. NVIDIA DGX H100/H200 and B200 ship locking C19/C20 cords rated 250 VAC, 20 A, 1200 mm.

One server and one PDU

Dell PowerEdge R760 with the 2400 W PSU in this catalog uses a C20 inlet. APC AP8941 has 21 C13 outlets and 3 C19 outlets. The jumper is C19–C20: C19 into the R760, C20 into one C19 outlet. A lower-watt R760 PSU can be C14 and then uses a C13 outlet instead.

Worked pair: R760 + AP8941.