A robotic working tool comprising a sensor for detecting magnetic fields connected to a controller for controlling the operation of the robotic working tool. The controller is configured to operate according to a first control signal being transmitted through a first boundary wire and according to a second control signal being transmitted through a second boundary wire. The robotic working tool is thereby configured to operate within a composite work area comprising at least a first partial work area and a second partial work area. The first boundary wire delimits the first partial work area and the second boundary wire delimits the second partial work area. The at least first and second boundary wires provide a common perimeter for the composite work area. Analysing the magnetic fields detected by the sensor, the controller determines whether the robotic working tool is inside or outside the composite work area.
