In one embodiment, an alternating circuit (AC) power connected node in a shared-media communication network (with knowledge of a current time) determines a time value of a particular zero-crossing event of the AC power, and sends a message to a neighbor node indicating the time value of the particular zero-crossing event to allow the neighbor node to synchronize its time by coordinating the time value to its detection of the particular zero-crossing event. In another embodiment, the neighboring node determines one or more local zero-crossing events of the AC power, such that upon receiving the message indicating a correct time value of the particular zero-crossing event, the neighboring node can synchronize its local time a current time by matching one of the one or more local zero-crossing events to the particular zero-crossing event and assigning the correct time value to the matched local zero-crossing event.