System and methods for determining loading on supply lines of a three-phase power distribution system. Load meters are connected to the supply lines to receive power. A feeder meter is connected to a supply line designated the reference supply line having a known reference phase. A device generates a timing pulse received by the load meters and the feeder meter. The load meters and feeder meter each determine a respective time delay and feeder meter delay from receiving the timing pulse until a landmark value of the power received. The feeder meter delay corresponds to the reference phase. Each load meter and feeder meter includes a transmission device to transmit the time delay or feeder meter delay. An end server receives the time delays and feeder meter delay and assigns each load meter to a phase by comparing the time delay for a load meter to the feeder meter delay.