Abstract: In an electrical safety system primarily for controlling the insertion of absorber rods into a nuclear reactor core in response to a trip signal, two groups of switches are connected between a power supply and the rod magnets. One group of switches is controlled by signal converters which receive input signals from respective guardlines. The other group of switches is controlled by opto-isolator/photo-detector links which also receive the input signals from the guardlines. If fault conditions in the reactor are sensed by more than one of a group of fault sensors, the feeding of the input signals to the signal converters and the optical links is inhibited, and the switches open, thereby deenergizing the magnets.