Electrotechnical standards published in Europe by CENELEC and based on IEC standards have so far been numbered EN 6xxxxx. Due to a revised cooperation agreement between IEC and CENELEC, the European standards will be called EN IEC 6xxxx as of 1 January 2018. There should be no retroactive numbering adjustments. Designs are also referred to as prEN 6xxxx or FprEN 6xxxx. If European standards are adopted by IEC in modified form, they will continue to be referred to as EN 6xxxx.
