A complete system design for the end-to-end time synchronization between end devices of a Phasor Measurement Unit (PMU) application over a Broadband Power Line Communications (BPL) network has been conceived. It is foreseen that BPL modems will be installed within secondary substations enabling communications over the electric grid as part of a larger system for mission- and time-critical grid monitoring and automation (MTC-GMA) applications. State estimation and fault location are examples of such applications requiring a PMU and are considered as reference applications for this project. The first step in the process was to capture the relevant use-cases and the resulting application requirements for the BPL time synchronization. Although each application has different requirements, the strictest requirement is that the time-synchronization solution must provide an end-to-end accuracy over the BPL network of ± 3.1 microseconds. This was followed by a design phase in which both the necessary digital signal processing as well as network protocol required for the time-synchronization have been developed using model based design and simulations. A system design has been defined allowing each BPL cell to not only synchronize all devices within the cell, but also synchronize to the absolute time outside of the cell. End-to-end synchronization is realized by providing a standardized interface between the BPL modems and end devices based on a one pulse per second (1PPS) signal. The synchronization solution has been realized on top of HSLU’s existing Power Line data bUS (PLUS) BPL technology. Tests have been carried out in a laboratory environment on realistic channel conditions and it has been shown that an accuracy in the range of ± 0.5 μs can be achieved over two “hops” in the network. Work continues in a follow-up project for developing a complete MTC-GMA BPL system.