SE.1 Application to existing overhead lines This Part 2-18 is applicable for new overhead lines only and not for existing lines. SE.2 Maintenance, rebuilding or extension of an overhead line Measures related to maintenance of the electrical installation shall fulfill the legislation in force when it was erected. In the case of a rebuilding or extension of an electrical installation (overhead line), the regulations in force shall be applied for the rebuilding or extension. (ELSÄK-FS 2008:1) SE.3 Replacement This Part 2-18 replaces the Swedish Standards SS EN 50341 3 18, edition 1 and SS EN 50423 3 18, edition 3. SE.4 Optical ground wire (OPGW) and optical phase conductor (OPCON) This Part 2-18 is applicable for installation of OPGW and OPCON, also known as OPPC, in overhead lines in Sweden. SE.5 All dielectric self supporting optical cable (ADSS) and optical attached cable (OPAC) This Part 2-18 is applicable for installation of ADSS and OPAC in overhead lines in Sweden. NOTE The allowable electrical field for the ADSS cable should be taken into consideration when the conductor configuration is determined.