Patent ID: 8639459

Claim:
A data center, comprising: one or more racks; one or more electrical systems mounted in at least one of the racks; one or more rack power distribution units (PDUs) in at least one of the racks, wherein at least one of the rack PDUs is configured to distribute electrical power to at least part of the electrical systems in at least one of the racks; one or more rack PDU power monitors configured to externally couple to at least one of the rack PDUs and to monitor electrical power from at least one of the rack PDUs, wherein at least one of the rack PDU power monitors comprises: one or more PDU coupling devices configured to be coupled with one or more PDU output receptacles of one or more of the rack PDUs on a downstream side of the one or more PDU output receptacles; and a monitoring device coupled to the one or more PDU coupling devices, such that the monitoring device is externally coupled to the at least one of the rack PDUs, wherein the monitoring device is configured to monitor electrical power output from at least one of the PDU output receptacles.