The International Organization for Standardization is an international standard-setting body composed of representatives from various national standards organizations.
The International Electrotechnical Commission is an international standards organization that prepares and publishes international standards for all electrical, electronic area.
The European Committee for Standardization is a public standards organization. The Members of CEN are the National Standardization Bodies of 34 European countries.
European Committee for Electrotechnical Standardization. CENELEC is responsible for European standardization in the area of electrical engineering.