-A method for detecting a fault in the electric power supply of a vehicle, the vehicle comprising an electrical power train, a collection device for collecting electrical current from an external supply line and an energy storage device, the collection device being electrically connected to the power train and to the energy storage device, the method comprising the steps of: - measuring, by means of a current sensor of the vehicle, the intensity of an electric current (Ic) flowing through the current collection device; - comparing the measured current, by means of an electronic control unit of the vehicle, with a first predefined current threshold value (Imax); - if the measured current (Ic) is greater than or equal to the first current threshold value (Imax), counting, by means of the control unit, an accumulated value of electrical energy (Eacc) that transits through the collection device over time; - comparing, repeatedly, by means of the electronic control unit, the accumulated electrical energy value (Eacc) with a first predefined energy threshold value (Emax); - controlling the electrical disconnection of the collection device from the external supply line or the power train and the electrical storage device, by means of the control unit, when the cumulative energy value (Eacc) becomes greater than or equal to the first energy threshold value (Emax), the collection device not being disconnected as long as the cumulative electrical energy value remains less than the first energy threshold value; wherein the first current threshold value (Imax) and the energy threshold value (Emax) are selected as a function of characteristics of the collection device and the external supply line and of the interface between the collection device and the external supply line, and in particular of their ability to withstand a temperature rise for a given period of time, and wherein the method further comprises the steps consisting of: - acquiring, by means of an electronic command device of the vehicle, a second current threshold value (I lim) and a second time threshold value (t lim); - if the measured current value (Ic) is greater than or equal to the second current threshold value (I lim) for a period of time (t) greater than or equal to the second time threshold value (t lim), commanding the electrical disconnection of the collection device from the external power supply line or the power train and the electrical storage device, by means of the command device. - measuring, by means of a current sensor of the vehicle, the intensity of an electric current (Ic) flowing through the current collection device; - comparing the measured current, by means of an electronic control unit of the vehicle, with a first predefined current threshold value (Imax); - if the measured current (Ic) is greater than or equal to the first current threshold value (Imax), counting, by means of the control unit, an accumulated value of electrical energy (Eacc) that transits through the collection device over time; - comparing, repeatedly, by means of the electronic control unit, the accumulated electrical energy value (Eacc) with a first predefined energy threshold value (Emax); - controlling the electrical disconnection of the collection device from the external supply line or the power train and the electrical storage device, by means of the control unit, when the cumulative energy value (Eacc) becomes greater than or equal to the first energy threshold value (Emax), the collection device not being disconnected as long as the cumulative electrical energy value remains less than the first energy threshold value; wherein the first current threshold value (Imax) and the energy threshold value (Emax) are selected as a function of characteristics of the collection device and the external supply line and of the interface between the collection device and the external supply line, and in particular of their ability to withstand a temperature rise for a given period of time, and wherein the method further comprises the steps consisting of: - acquiring, by means of an electronic command device of the vehicle, a second current threshold value (I lim) and a second time threshold value (t lim); - if the measured current value (Ic) is greater than or equal to the second current threshold value (I lim) for a period of time (t) greater than or equal to the second time threshold value (t lim), commanding the electrical disconnection of the collection device from the external power supply line or the power train and the electrical storage device, by means of the command device. - acquiring, by means of an electronic command device of the vehicle, a second current threshold value (I lim) and a second time threshold value (t lim); - if the measured current value (Ic) is greater than or equal to the second current threshold value (I lim) for a period of time (t) greater than or equal to the second time threshold value (t lim), commanding the electrical disconnection of the collection device from the external power supply line or the power train and the electrical storage device, by means of the command device.