A method for avoiding function disablements of intelligent electronic units IEDs that are connected in a local network which has at least two timing units. One of the timing units assumes an active grandmaster role as a synchronization source while the other timing units remain in their slave state and synchronize with the timing unit in the grandmaster role. When one of the timing units changes from the slave state to the grandmaster role, a pre-synchronization message is used to notify all IEDs in the local network whether and, if applicable, with which previous grandmaster timing unit the present grandmaster timing unit was synchronized. This avoids a disablement of the function of the IEDs that generate or process data streams whose samples have been acquired in sync with the previous grandmaster timing unit.