The three-phase, four-cable type of power distribution lines branch into multiple circuits from local pole- or pad-mounted transformers, which makes the topology of lines complicated. A challenging issue is how to trace cables and transformers in a complicated distribution system. The proposed idea is based on a power line carrier signal, which has certain propagation characteristics along the distribution system. This novel and live tracing methodology, called the synchronized client and server method, is introduced, designed, and implemented to trace cables and transformers in the distribution system. The most difficult part of cable tracing is to isolate the signals needed for tracking from a mixture of signals routed through transformers or loads and signals transmitted directly along a test line. The algorithms needed to isolate the signals have been developed and a zero crossing sensor module is designed to ensure that the remote client and server are in phase. Simulations have been carried out to verify the proposed system using a Simulink simulator. Experiments have been conducted to verify the theoretical concepts in a test bed and a commercial building. Finally, the theory has been proved at a resolution of 0.5 ms from comparisons between the simulations and the experiments.