Load balancing of phases of a power distribution unit

A power distribution unit 100 comprising a multi-phase power supply input 102, several power supply sockets 1040-1052 each for supplying a device 1060-1072 with single-phase power, several multi-phase controllable switches 1080-1092 to connect the phase of each socket to one of the phases of the multi-phase input, a power load monitor 110 for monitoring the load of each phase of the multi-phase input by devices connected to and supplied by the sockets and/or the power load of the sockets, and a switch controller 112 for controlling the switches and changing the load of each phase of the multi-phase power supply input and/or each power supply socket. The controller may control the switches so that the load of each phase is equally distributed. This may be done by determining the phases with the highest and lowest loads and controlling the switches to connect a socket connected to the highest load to the lowest load in an iterative process.