Update to earthing standard BS EN 50522
The European standard for the earthing of power installations exceeding 1 kV AC has undergone what the British Standards Institute (BSI) has called ‘a complete technical revision’.
The standard is aimed at any client, organisation or person working with HV electrical systems in the built environment. This includes the specification, design, manufacture, procurement, construction, inspection, assessment, management, operation, maintenance, refurbishment or demolition of these systems.
The new standard was published in the UK in February 2023 as BS EN 50522:2022, meaning the older version, BS EN 50522:2010, is now obsolete.
What has changed?
BSI has provided a list of the major changes in BS EN 50522:2022, which are:
- Text sections in italic, indicating that the section is a copy of an IEC 61936-1 text, are replaced by a reference note to IEC 61936-1 for copyright reasons
- Clause 3 is updated regarding touch voltages
- Figures in Clause 3 for distribution of earth fault currents are improved
- The process of designing an earthing system is clarified in 5.4 and Figure 9
- Annex A and B are rearranged to include prospective permissible touch voltage and permissible step voltage
- Stainless steel is introduced in Annex C and Annex D
- More details and figures are given regarding fences in Annex G
- Annex I has an enlarged table on cable reduction factors and application
- New figures are added in Annex J (J.4 and J.5)
- Annex L features new details on soil resistivity measurements and touch voltage measurements including a flow chart
- Clause 10 was Annex M in the previous version
BS EN 50522:2022 is available to purchase from BSI. ATLAS members get free access to the standard as a benefit of their ATLAS membership, along with many other lightning protection and access related standards.
There is more information on this standard on the BSI website, including an executive briefing that includes details of how it should be used.
