the aircraft 10 is powered with electricity by the generator set 20 thanks to a power supply cable 30 comprising several electrical conductors and at the end of which is set an end connector 40 having an electrical contact for each electrical conductor . the aircraft 10 has a connection terminal 50 having , for each electrical conductor , an electrical contact downstream of which is connected a conductor 14 embedded in the aircraft 10 and to which is connected at least one electrical component 12 of the aircraft 10 to be protected . the extension socket 60 also comprises a first connector 62 which for each electrical conductor from the generator set 20 has an electrical contact which can be electrically connected to the said electrical conductor by means of an end connector 40 . the extension socket 60 also comprises a second connector 64 which has , for each electrical contact of the first connector 62 , an electrical contact 65 which is electrically connected to the said electrical contact of the first connector 62 and therefore to the associated electrical conductor . each electrical contact 65 is designed to be connected to an electrical contact of the connection terminal 50 , an embedded conductor 14 being connected downstream of said electrical contact to electrical components 12 to be protected . the extension socket 60 also comprises a third connector 66 which has , for each electrical contact of the first connector 62 , a female electrical contact 68 which is electrically connected to the said electrical contact of the first connector 62 and therefore to the associated electrical conductor . in the context of the invention , the third connector 66 seats the safety device 100 . of course , it is possible to provide an extension socket of another type where the electrical conductors a , b , c , e , f and n have a different layout and their number is different . a housing 102 made of electrically insulating material ; for each female electrical contact 68 , a male electrical contact 106 made of electrically conductive material , projecting from the housing 102 and designed to be inserted in the said female electrical contact 68 ; clipping means 108 designed to clip an electrical signal ; a printed circuit 104 seated inside the housing 102 and having conductive tracks connecting the male electrical contacts 106 and the clipping means 108 . thus , by connecting the safety device 100 onto the third connector 66 , an electrical overvoltage on one of the electrical conductors is clipped by the clipping means 108 and the components of the aircraft 10 are protected . during normal mode , the clipping means 108 are transparent , while , beyond a certain voltage the clipping means 108 will clip the signal . fig4 shows a diagram of an electric circuit 200 of the printed circuit 104 of the safety device 100 in a preferred embodiment . in this embodiment the first electrical conductors a , b and c are electrical conductors carrying a low voltage current which is preferably of the order of 115 - 200v at 400 hz , the two electrical conductors e and f are electrical conductors carrying a very low voltage current which is preferably of the order of 28v and 0 . 5v and the third electrical conductor n is the neutral connected to earth . the first electrical conductors a , b and c are the phase conductors . the two electrical conductors e and f are called “ discrete command conductors ”. clipping means 108 a , 108 b are arranged between each male electrical contact 106 corresponding to a first electrical conductor a , b and c or to a second electrical conductor e and f , i . e . an electrical conductor a , b , c , e , f other than neutral n , and the male electrical contact 106 corresponding to neutral n . the clipping operation thus consists , in the case of an electrical overvoltage in an electrical conductor a , b , c , e , f , in setting this electrical conductor to the neutral which is itself connected to the earth of the aircraft 10 . preferably , each clipping means 108 a , 108 b is an assembly consisting of a diode 204 or several diodes 202 mounted in series between the male electrical contact 106 corresponding to each electrical conductor a , b , c , e , f other than neutral n and the male electrical contact 106 corresponding to neutral n . in this embodiment of the invention , when the voltage in the electrical conductor a , b , c , e , f exceeds the limit voltage ( also called “ inversion voltage ” or “ clipping voltage ” or also “ clamping voltage ”) of the diode or diodes 202 , 204 , the latter are switched from a blocking state to a conducting state and start to conduct and transfer the electrical overvoltage towards the neutral n which is itself connected to the earth of the aircraft 10 . for each electrical conductor a , b , c , e , f , other than neutral n , departing from the generator set 20 , the characteristics and the number n of diodes 202 , 204 are chosen depending on the conditions of use of the safety device 100 . the characteristics of a diode 202 , 204 are as follows : the transition time between the blocking state and the conducting state , the maximum current intensity able to flow in the diode 202 , 204 , and the limit voltage at which the diode starts to conduct . the current intensity during the overvoltage , for each electrical conductor , the maximum voltage flowing in the said electrical conductor ( with preferably a margin of 10 to 15 % corresponding to the conventional fluctuations of the voltage flowing in the generator set 20 ), and the time interval for which each electrical component 12 to be protected may accept an overvoltage without suffering damage . for an electrical conductor and the associated embedded conductor 14 , each diode 202 , 204 is firstly chosen so that its transition time is less than the time for which the electrical component 12 to be protected and electrically connected to the said embedded conductor 14 may be exposed to an overvoltage without damage ; among these diodes 202 , 204 , only those diodes 202 , 204 which have a maximum current intensity able to flow therein greater than the current intensity during the overvoltage are retained . for each model of diodes 202 , 204 which satisfies these two criteria and for each electrical conductor , the number n of diodes is thus the integral which is marginally greater than the ratio between the maximum voltage flowing in the electrical conductor and the limit voltage of the diode 202 , 204 . with a view to optimization , the diode 202 , 204 for which n is the smallest is chosen . it is also possible to take into account additional criteria . for example , the diodes 202 , 204 which have a lower residual voltage will be preferred , preference being given to the diodes 202 , 204 able to dissipate a greater power . in the case of the first electrical conductors a , b and c , the clipping means 108 a consist of four diodes 202 which are identical and mounted in series . in the case of the two electrical conductors e and f , the clipping means 108 b consist of a diode 204 . the diodes 202 , 204 are for example diodes which are identified by the reference code 30kpa54ca or 30kpa58ca of the manufacturers littlefuse . the safety device 100 and the extension socket 60 form a socket system according to the invention which is connected to the plurality of electrical conductors . in order to prevent the humidity or the dust from entering into the female electrical contacts 68 and the male electrical contacts 106 , the housing 102 is sealingly mounted on the extension socket 60 . according to a particular embodiment of the invention , the length of the conductor between the male electrical contact 106 corresponding to neutral n and the earth is less than 0 . 85 m and its resistance is less than 50 μω . while at least one exemplary embodiment of the present invention ( s ) is disclosed herein , it should be understood that modifications , substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure . this disclosure is intended to cover any adaptations or variations of the exemplary embodiment ( s ). in addition , in this disclosure , the terms “ comprise ” or “ comprising ” do not exclude other elements or steps , the terms “ a ” or “ one ” do not exclude a plural number , and the term “ or ” means either or both . furthermore , characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise . this disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority .