A perforating safety system. A perforating safety system includes a detonation transfer interrupter with a device which decreases an axial separation between detonation transfer components after installation of the interrupter in the well. Another perforating safety system includes a perforating gun and firing head installed together in the well, and an interrupter having a device which increases a separation between detonation transfer components in the well to thereby prevent transfer of detonation from the firing head to the perforating gun. Yet another perforating safety system includes a firing head positioned at a distal end of a perforating assembly when installed in the well, and an interrupter having a device which decreases a separation between detonation transfer components after installation of the interrupter in the well.