Set comprising: - a generator set comprising a power supply cable comprising several electrical conductors and at the end of which is set an end connector having an electrical contact for each electrical conductor, - an aircraft powered with electricity by means of said generator set thanks to a power supply cable and having a connection terminal having, for each electrical conductor, an electrical contact downstream of which is connected a conductor embedded in the aircraft and to which is connected at least one electrical component of the aircraft, and - a socket system for the protection against lightening comprising: - an extension socket connected between the end connector and the connection terminal and comprising: - a first connector connected to the end connector and having, for each electrical conductor of the end connector, an electrical contact electrically connecting to said electrical conductor of the end connector, - a second connector having, for each electrical contact of the first connector, an electrical contact which is electrically connected to said electrical contact of the first connector and connecting to an electrical contact of the connection terminal, - a third connector having, for each electrical contact of the first connector, a female electrical contact electrically connected to said electrical contact of the first connector, and the set being characterized in that it further comprises a safety device connected to the third connector and comprising: - a housing made of electrically insulating material; - for each female electrical contact, a male electrical contact projecting from the housing and designed to be inserted in the said female electrical contact; - clipping means (108, 108a, 108b) designed to clip an electrical signal; - a printed circuit seated inside the housing and having conductive tracks connecting each male electrical contact to a clipping mean (108, 108a, 108b). - a generator set comprising a power supply cable comprising several electrical conductors and at the end of which is set an end connector having an electrical contact for each electrical conductor, - an aircraft powered with electricity by means of said generator set thanks to a power supply cable and having a connection terminal having, for each electrical conductor, an electrical contact downstream of which is connected a conductor embedded in the aircraft and to which is connected at least one electrical component of the aircraft, and - a socket system for the protection against lightening comprising: - an extension socket connected between the end connector and the connection terminal and comprising: - a first connector connected to the end connector and having, for each electrical conductor of the end connector, an electrical contact electrically connecting to said electrical conductor of the end connector, - a second connector having, for each electrical contact of the first connector, an electrical contact which is electrically connected to said electrical contact of the first connector and connecting to an electrical contact of the connection terminal, - a third connector having, for each electrical contact of the first connector, a female electrical contact electrically connected to said electrical contact of the first connector, and the set being characterized in that it further comprises a safety device connected to the third connector and comprising: - a housing made of electrically insulating material; - for each female electrical contact, a male electrical contact projecting from the housing and designed to be inserted in the said female electrical contact; - clipping means (108, 108a, 108b) designed to clip an electrical signal; - a printed circuit seated inside the housing and having conductive tracks connecting each male electrical contact to a clipping mean (108, 108a, 108b). - an extension socket connected between the end connector and the connection terminal and comprising: - a first connector connected to the end connector and having, for each electrical conductor of the end connector, an electrical contact electrically connecting to said electrical conductor of the end connector, - a second connector having, for each electrical contact of the first connector, an electrical contact which is electrically connected to said electrical contact of the first connector and connecting to an electrical contact of the connection terminal, - a third connector having, for each electrical contact of the first connector, a female electrical contact electrically connected to said electrical contact of the first connector, and - a first connector connected to the end connector and having, for each electrical conductor of the end connector, an electrical contact electrically connecting to said electrical conductor of the end connector, - a second connector having, for each electrical contact of the first connector, an electrical contact which is electrically connected to said electrical contact of the first connector and connecting to an electrical contact of the connection terminal, - a third connector having, for each electrical contact of the first connector, a female electrical contact electrically connected to said electrical contact of the first connector, and - a housing made of electrically insulating material; - for each female electrical contact, a male electrical contact projecting from the housing and designed to be inserted in the said female electrical contact; - clipping means (108, 108a, 108b) designed to clip an electrical signal; - a printed circuit seated inside the housing and having conductive tracks connecting each male electrical contact to a clipping mean (108, 108a, 108b).