This part of IEC 63093 specifies the dimensions that are of importance for mechanical interchangeability for a preferred range of EC-cores made of ferrite and the essential dimensions of coil formers to be used with them, as well the effective parameter values to be used in calculations involving them. It also gives guidelines on allowable limits of surface irregularities applicable to EC-cores.
The specifications contained in this document are useful in negotiations between ferrite core manufacturers and customers about surface irregularities.