Your larger question should be what type of 220 circuit does the customer have.

There are a number of different plugs based on the amps and if they are locking or non locking.

For 220 you will most likely have some form of 6-xx where xx is the amp rating.

The end on the router is called a C13 so its just a matter of getting the correct ends.

Been a while since I saw a part number for a cisco cable. But this link has diagrams of 2 of the 3 more "common" 220v cables you will find in the US. Not that this is a common thing to really do.

The electrician that installed the 220 circuit for them should be able to provide a power cord.

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/hw/installation/guide/portcabl.html