scope:

General

FI.1 Application of the standard in Finland

In Finland, the standard EN 50341-1 (Part 1) can only be applied using this NNA (EN 50341- 2-7) containing National Normative Aspects for Finland.

The requirements of the standard are applied also for low voltage (below 1 kV AC) overhead lines. The requirements of the structural design are applicable also for DC overhead lines, where the electrical requirements are given in the Project Specification.

This standard is applicable for new overhead lines only.

FI.2 Application for existing overhead lines

Overhead lines complying with the mechanical and electrical requirements of its original date of construction can be operated and maintained, if they do not cause obvious danger.

The reparation and overhaul of lines can be done according to the previous requirements. Reparation means that a component which has been damaged is substituted with a similar new one. Overhaul means a wider improvement of the line for extending its lifetime. The basic structure remains same as before.

This standard should be used for all modification works on existing lines. In the modification works, earlier norms and standards may also be used, if allowed by the valid Electrical Safety Act. In that case it shall especially be verified that changes in actions do not cause significant increase in the loads of the line. Modification work means e.g. relocation of some supports or an extension to a line by addition of a circuit or changing of the conductors to existing supports.

Field of application

FI.1 Application to covered conductors and aerial cables

The standard includes requirements for the design and construction of overhead lines equipped with covered conductors and aerial cables. Additionally, the requirements of the equipment standards and manufacturers' instructions shall be considered.

FI.2 Installation of other equipment

Only equipment belonging to the line (electric or telecommunication line) can be installed on the overhead line supports. However, equipment serving communal services or environmental protection like telecommunication equipment, road signs, warning signs or warning balls may also be installed with the permission of the owner of the line.

With the permission of the owner of the line, also other equipment than those mentioned above, can be installed on supports of the line equipped with aerial cables.

If other equipment is installed on the supports, the requirements of safe working practices shall be considered. The installation height of equipment meant to be installed and maintained by an ordinary person shall be such that the work can be done without climbing the support and the distances of safe electrical work can be followed (see standard SFS 6002).

The additional loads due to other equipment to the line shall be considered.