The invention is a sensor (15) for welding and/or cutting systems comprising a generator (4), a welding and/or cutting torch (1) and a connection element (40) comprising one or more power supply cables (lib) of the torch and/or one or more control cables of the torch the sensor (15) is such that it is suited to detect the passage of current in at least one of said one or more cables of the connection element (40) the sensor (15) is such that it comprises a ferromagnetic circuit (19) that at least partially envelops said at least one of said one or more cables of the connection element (40) and a Hall sensor (18). The invention furthermore concerns a welding and/or cutting unit comprising a current sensor (15).
