On the R640 10 bay is an expansion board that sits in front of the backplane. This is the power cable that routes from the expansion board to the left rear of the chassis. It plugs into the J_BP2 power connector.
Installation:
On the cable itself is an end labeled EXP. This plugs into the expansion board. The other end plugs into the J_BP2 connector as show below. Connector is right below J_BP1. Note, cable not shown. Only the connector.
