scope:

This NNA determines the requirements which shall be fulfilled while designing and constructing of new overhead lines with nominal system voltages exceeding 1 kV AC. The scope of use of this NNA for temporary lines shall be determined by the Project Specification. For modernisations, reconstructions and refurbishments of the existing lines, the scope and the requirement to comply with PN-EN-50341-1, together with this NNA, shall be determined by the Project Specification. This NNA applies to overhead lines with covered conductors and overhead insulated cable system with nominal voltage exceeding 1 kV up to 45 kV AC. Additional requirements and simplifications, which apply only to this range of voltages, have been determined. This NNA does not contain requirements applicable for designing and constructing overhead lines with nominal voltage exceeding 45 kV AC, with covered conductors, where internal and external clearances can be smaller than specified in the NNA.