A switch is disclosed for power distribution, in particular a circuit breaker and compact switch, which automatically interrupts the electric currents flowing through the switch in a polyphase electrical power supply system when a tripping situation occurs. In at least one embodiment, the switch includes switching contacts which are provided for each phase and can be opened via a switching shaft; an electronic release which automatically initiates the opening of the switching contacts via the switching shaft; electrical power converters, which in each case take the electrical power which is required for the electrical power supply for the release from the currents for the individual phases; instrument transformers which convert the currents in each of the individual phases to a measurement signal; an electronic circuit, in particular in the form of a microprocessor, for assessment of the current values which correspond to the measurement signals, wherein the occurrence of the tripping situation is in each case identified on the basis of the assessment. In order to improve the functional reliability of the switch, in at least one embodiment it is proposed that the currents emitted from the power converters are additionally recorded and that the electronic circuit carries out a plausibility comparison on the basis of the recorded current of the power converters and of the instrument transformers, and generates a warning signal in the event of non-plausibility.