A current sensor including a housing, the housing including a first module adapted to be clamped around a wire part of a power cable; a second module having a processing unit and a communication unit; the first module further including a device to measure the current through the wire of said power cable and to send the measured current to the processing unit through a first communication link. The processing unit includes a first time tracker; where the processing unit further includes software/hardware to increment the first time tracker if the measured current is above a first predetermined threshold and in that the communication unit includes a GSM module adapted to wirelessly transmit the value of the first time tracker.