Server power requirements
The vendor's product spec sheet should give you the number of PSUs and their rating. For example, this spec sheet specifies either two or four PSUs and the picture of the rear of the system shows the power connectors. While the spec sheet does not say it explicitly, these look like C20 connectors. Other vendors will publish similar sheets for their servers. FYI, the more standard C13 power cord is more common on lower-end servers.