A power distributor having a first controller and having a number of connection modules which are connected thereto and are intended to be mounted on a supporting rail. The connection module has a number of lateral coupling contacts for the electrical and/or signalling contact connection to at least one further connection module which is attached or can be attached to the particular connection module, wherein a base resistor is connected in each case between two coupling contacts inside the module in such a manner that the base resistors of the attached connection modules form a resistor chain which is connected in series. The connection modules are each equipped or can be equipped with an actuatable circuit breaker. The circuit breakers have a second controller inside the circuit breaker for recording a voltage dropped across the respectively associated base resistor.