The International Electrotechnical Commission (IEC) decided in 1988 to produce a civil standard on the electromagnetic effects of a high altitude EMP (HEMP). Different documents pertaining to the radiated environment and to specifications and test methods have been elaborated and are circulated. A standard conducted environment dependent on many parameters is, however, more difficult to define. The authors present a probabilistic approach which has been adopted to define a typical current shape for the conducted environment. The distribution functions of the peak current value for horizontal and vertical polarizations based on 1710 calculated cases reflecting a variation of the elevation and azimuthal angles from 0 to 90° are presented and discussed