A socket system for the protection against lightening of an aircraft disposed between a connection terminal of the aircraft and an end connector of a generator set powered by a power supply cable having several electrical conductors includes an extension socket connected between the end connector and the connection terminal and a safety device including in a housing made of electrically insulating material, and clipping means designed to clip an electrical signal. The installation of such a safety device prevents the propagation of an electrical overvoltage beyond the safety device.