EN 50341-2-20:2018

Overhead electrical lines exceeding AC 1 kV - Part 2-20: National Normative Aspects (NNA) for ESTONIA (based on EN 50341-1:2012) EN 50341-2-20:2018

Publication date:   Jun 17, 2019

Scope

General
(snc) EE.1 Application to new lines
In Estonia the standard EN 50341-1 (Part 1) can only be applied using this NNA (EN 50341-2-20) containing National Normative Aspects for Estonia.
This Part 2-20 applies to all new overhead electric lines with nominal system voltages exceeding AC 1 kV and also for low voltage (below 1 kV AC) overhead lines performed by aerial cables. The requirements of the structural design are applicable also for DC overhead lines, where the electrical requirements are given in the Project Specification.
(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. Specific requirements for junction support should be defined with the Project Specification.
1.2 Field of application
(ncpt) EE.1 Application to covered conductors and aerial cables
The standard includes requirements for the design and construction of overhead lines with nominal system voltages up to 45 kV AC equipped with covered conductors and aerial cables. Additionally, the requirements of the equipment standards and manufacturers’ instructions shall be followed.
(A-dev) EE.2 Application to mounting of telecommunication equipment
The Standard EVS-EN 50341:2013 is applicable to fixing of structural elements for tele-communication (antennas, All Dielectric Self Supporting (ADSS) equipment, junction boxes, 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 the line owner and stated in the Project Specification.
This standard applies to telecommunication lines only in the case of their common installation with power lines. This standard does not apply to separately installed telecommunication overhead lines.
If telecommunication equipment (antennas, dishes, etc.) will be installed in the transmission line supports, and their size, location or mounting may have major effects on the loads or design of the structures, the requirements of EVS-EN 1993-3-1/NA:2009 shall also to be taken into account. If such structures include conductive parts, the requirements on clearances in subclause 5.8 should be applied.
(ncpt) EE.3 Application to installation of other equipment
Only equipment belonging to the line (electric or telecommunication line) can be installed on the overhead lines. However, with the permission of the owner of the line, equipment serving communal services or environmental protection like road signs, warning signs or warning balls, etc., may also be installed. The installation height of equipment meant to be installed and maintained by an instructed person shall be such that the work can be done without climbing the support and the distances of safe electrical work can be followed. The additional loads due to this equipment on the line supports shall be taken into account if necessary.