European Committee for Electrotechnical Standardization

Earthing of power installations exceeding 1 kV a.c.
 N EN 50522

Annotation

This European Standard 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 a.c. and nominal frequency up to and including 60 Hz, so as to provide safety and proper functioning for the use intended.

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

a) substation, including substation for railway power supply;

b) electrical 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 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.

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

– rotating electrical machines;

– switchgear;

– transformers and reactors;

– converters;

– cables;

– wiring systems;