UNE-EN 50522:2022

This document is applicable to specify the requirements for the design and erection of earthing systems of electrical installations, in systems with nominal voltage above 1 kV AC and nominal frequency up to and including 60 Hz, so as to provide safety and proper functioning for the use intended.

NOTE 1 The technical and procedural principles of this document can be applied when 3rd parties installations and facilities are planned and/or erected in the vicinity of HV electrical power installations.

For the purpose of interpreting this document, an electrical power installation is considered to be one of the following:

a) substation, including substation for railway power supply;

b) electrical power installations on mast, pole and tower;

switchgear and/or transformers located outside a closed electrical operating area;

c) one (or more) power station(s) located on a single site;

the electrical power installation includes generators and transformers with all associated switchgear and all electrical auxiliary systems. Connections between generating stations located on different sites are excluded;

d) the electrical system of a factory, industrial plant or other industrial, agricultural, commercial or public premises;

e) electrical power installations on offshore facilities for the purpose of generation, transmission, distribution and/or storage of electricity;

f) transition towers/poles between overhead lines and underground lines.

The electrical power installation includes, among others, the following equipment:

rotating electrical machines;

switchgear;

transformers and reactors;

converters;

cables;

wiring systems;

batteries;

capacitors;

earthing systems;

buildings and fences which are part of a closed electrical operating area;

associated protection, control and auxiliary systems;

large air core reactor.

NOTE 2 In general, a standard for an item of equipment takes precedence over this document.

This document does not apply to the design and erection of earthing systems of any of the following:

overhead and underground lines between separate installations;

NOTE 3 The standard, EN 50341 series Overhead lines exceeding AC 1 kV, specifies requirements for the design and erection of earthing systems in overhead lines.

electrified railway tracks and rolling stock;

mining equipment and installations;

fluorescent lamp installations;

installations on ships and off-shore installations;

electrostatic equipment (e.g. electrostatic precipitators, spray-painting units);

test sites;

medical equipment, e.g. medical X-ray equipment.

NOTE 4 The scope of this document does not include the requirements for carrying out live working on electrical power installations.

NOTE 5 The scope of this document considers safety requirements for HV installations and its influences on LV installations. For electrical installation up to 1 kV, the standard IEC 60364 series applies.