A method and corresponding apparatus provide a determination of available power capacity of a phase of a power supply in a data center rack. The method includes metering the power of a power supply and calculating an average peak power draw per phase of the power supply. Using average peak power draw per phase of the power supply and the expected power draw data corresponding to data center equipment coupled to the power supply, the available power capacity can be calculated on a per phase of the power supply. A method and corresponding apparatus for managing data center equipment may use the phase based available power capacity calculations to determine the optimal placement of new data center equipment within a data center configuration.