EN 50341-2-20:2015

0 Introduction
1 Scope
2 Normative references, definitions and symbols
3 Basis of design
4 Actions on lines
5 Electrical requirements
6 Earthing systems
7 Supports
8 Foundations
9 Conductors and earth-wires
10 Insulators
11 Hardware
12 Quality assurance, checks and taking-over
Annex B (informative) - Conversion of wind
        velocities and ice loads
Annex C (informative) - Application examples of wind
        loads - Special forces
Annex E (normative) - Theoretical method for calculating
        minimum air clearances
Annex F (informative) - Empirical method for calculating
        mid span clearances
Annex G (normative) - Calculation methods for earthing
        systems
Annex H (informative) - Installation and measurements
        of earthing systems
Annex M (informative) - Geotechnical and structural
        design of foundations

1.1General(NCPT)EE.1Application to new linesThis Part 2-20 applies to all new overhead electric lines with nominal system voltages exceeding AC 1 kV and with rated frequencies below 100 Hz. This standard also applies to D.C. overhead lines in structural aspects.(NCPT)EE.2“New overhead line”A “new overhead line” means a completely new line between two points, A and B. A new branch line of the existing power line should be considered as a new power line including the junction support, for which specific requirements should be defined in the Project Specification.1.2Field of application(A-dev)EE.1Application to mounting of telecommunication equipmentThe Standard EVS-EN 50341:2012 is applicable to fixing of structural elements for tele-communication (antennas, satellite dishes, All Dielectric Self Supporting (ADSS) equipment, etc.), if mounted on power line supports (towers), especially regarding wind forces and ice loads on such fixed elements. The design and installation should be done under the due control of the line owner and/or the competent authority. Mounting of telecommunication equipment on power line supports must be coordinated with line owner and stated in the Project Specification.If telecommunication equipment (antennas, dishes, etc.) will be installed in the transmission line supports, and their size, location or mounting will have major effects on the loads or design of the structures, the requirements of EVS-EN 1993-3 will also have to be taken into account. If such structures include conductive parts, the requirements on clearances in Section 5.8 should be applied.(NCPT)EE.2Application to existing overhead linesThe Standard EVS-EN 50341:2012 shall not be applied to maintenance, reconductoring, tee-offs, extensions or diversions to existing overhead lines in Estonia, unless specifically required in the Project Specification.In cases of major revisions of existing lines the degree of application of the Standard EVS-EN 50341:2012 should be agreed upon by the parties concerned and specified in the Project Specification.(NCPT)EE.3Application to installations under construction or designInstallations in the design and construction stage may be completed by using the standard valid at the beginning of planning unless otherwise agreed with the line owner and/or any other competent authority.It must also be determined in the Project Specification which previous National Standard and to what extent should be applied to the project in question.