A three-phase current sensor for measuring currents running in three conductors of a three-phase conductor system includes at least a first magnetic measuring device. The magnetic measuring device includes a magnetic circuit provided with at least two gaps and a magnetic field sensor arranged in each gap of the magnetic circuit. The magnetic field sensors are positioned on both sides of a cavity sized to receive one of the three conductors. The gaps and thus the magnetic field sensors are positioned such that stray magnetic flux from an adjacent conductor has substantially equal amplitude passing through each of the sensors.