A system for controlling electrical power supply of an aircraft includes at least two control boards and at least two switching members. Each switching member is connected to each control board. Each control board includes a processor. Each processor is configured to determine a command for switching states of switch contacts of each switching member and to determine information relating to validity of each switching command. Each switching member includes a transmitter to determine a command to be transmitted to a detector to detect parallelization, a power actuator configured to transmit a power signal to the switch contacts depending on the command received from the detector, and switch contacts configured to selectively open or close an electrical power supply line. The command is selected from the switching commands and the information relating to the validity of each switching command.