Since the 1970’s the Four Core System has been adapted in many Central and North European countries e.g. in Austria, Germany, Ireland, United Kingdom, Poland, Hungary, Russia and Scandinavia. The four equal insulated conductors, that share the tensile load equally, have size range of 16 to 185 mm². They are made of aluminium with a relatively high tensile strength. Therefore, the breaking load of the cable is relatively high, too.