Wireless electrical energy metering device comprising: - a current sensor designed to supply a secondary current (Is) from a primary electric current (Ip) flowing through an electrical conductor; - a primary electrical energy storage unit connected to said current sensor and designed to store an amount of electrical energy from the secondary electric current; - a voltage threshold detection unit connected to said primary electrical energy storage unit and designed to detect an exceedance of a voltage threshold at the terminals of the primary electrical energy storage unit; - a processing unit connected to said primary storage unit; - first switching means (Ty) controlled by the voltage threshold detection unit and configured to trigger a supply of electric power to the processing unit when said voltage threshold at the terminals of the primary electrical energy storage unit is exceeded; - a first wireless data transmitter connected to said processing unit and configured to send a message containing data representing the electric current flowing through said electrical conductor; - a secondary electrical energy storage unit connected to said primary storage unit; - a unit for measuring the voltage (SC_V) at the terminals of the secondary storage unit; - second switching means designed to be controlled by the processing unit and configured to trigger a transfer of energy from said primary storage unit to said secondary storage unit and to trigger a supply of power to said first wireless data transmitter when the voltage measured at the terminals of the secondary storage unit by said measurement unit exceeds a threshold, with a view to allowing said first wireless data transmitter to transmit a message containing data representing the electric current flowing through said electrical conductor, upon instruction from said processing unit. - a current sensor designed to supply a secondary current (Is) from a primary electric current (Ip) flowing through an electrical conductor; - a primary electrical energy storage unit connected to said current sensor and designed to store an amount of electrical energy from the secondary electric current; - a voltage threshold detection unit connected to said primary electrical energy storage unit and designed to detect an exceedance of a voltage threshold at the terminals of the primary electrical energy storage unit; - a processing unit connected to said primary storage unit; - first switching means (Ty) controlled by the voltage threshold detection unit and configured to trigger a supply of electric power to the processing unit when said voltage threshold at the terminals of the primary electrical energy storage unit is exceeded; - a first wireless data transmitter connected to said processing unit and configured to send a message containing data representing the electric current flowing through said electrical conductor; - a secondary electrical energy storage unit connected to said primary storage unit; - a unit for measuring the voltage (SC_V) at the terminals of the secondary storage unit; - second switching means designed to be controlled by the processing unit and configured to trigger a transfer of energy from said primary storage unit to said secondary storage unit and to trigger a supply of power to said first wireless data transmitter when the voltage measured at the terminals of the secondary storage unit by said measurement unit exceeds a threshold, with a view to allowing said first wireless data transmitter to transmit a message containing data representing the electric current flowing through said electrical conductor, upon instruction from said processing unit.