This part of IEC 62317 specifies the standards and existing projects dealing with dimensions of ferrite cores. It is intended that this standard will include ferrite cores which are widely used and referenced in industry, either because they are included in national standards, or because they are seen to have broad-based use in industry. Where applicable, it is intended that the existing industrial name for each standard part should appear with the part within this series. It is intended that this standard will exclude ferrite cores which are specialty cores with limited use. Also, special cores which are only marginal variations upon standard cores are excluded. Examples: E24/25 (USA) and E24,5 (Metric) are two similar parts, yet they are included separately in this series because they are national standards, widely used. E-187 (USA) and FEE19A (Japan) are two similar parts, yet they are included separately in this series because they are national standards, widely used. EP5 has small dimensional differences when comparing different manufacturers, yet only one EP5 is shown in this series, because they are only minor variations on the single basic part. A ferrite core produced by only one or two suppliers may generally be considered a specialty part, and not suitable as a standard core within this series. A ferrite core produced by three or more competing manufacturers may generally be considered to be a candidate to be included in this series. IEC publishes electrical standards for families of ferrite cores, as well as this series of dimensional standards for families of ferrite cores. Modifications to the ferrite cores listed in one type of standard should be reflected in the other type.