What is BS EN 50522 - Earthing of power installations about?
A revised European standard, BS EN 50522:2022 specifies electrical installation earthing system requirements for installations exceeding 1 kV a.c.
Download the free Executive briefing to learn more about how to implement the standard: https://www.bsigroup.com/en-GB/standards/bs-en-50522/
Who is BS EN 50522 - Earthing of power installations for?
- Machine manufacturers (small, medium and large enterprises)
- Health and safety bodies (regulators, accident prevention organizations, market surveillance, etc.)
- Machine users/employers (small, medium and large enterprises)
- Service providers, e.g. for maintenance (small, medium and large enterprises)
What does BS EN 50522 - Earthing of power installations cover?
BS EN 50522 specifies requirements for the design and erection of earthing systems for electrical installations in systems with nominal voltage above 1 kV AC and nominal frequency up to and including 60 Hz.
According to BS EN 50522, an electrical power installation is one of the following:
- Substation, including substation for railway power supply
- Electrical power installations on mast, pole and tower; switchgear and/or transformers located outside a closed electrical operating area
- 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
- The electrical system of a factory, industrial plant or other industrial, agricultural, commercial or public premises
- Electrical power installations on offshore facilities for the purpose of generation, transmission, distribution and/or storage of electricity
- 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: In general, a standard for an item of equipment takes precedence over BS EN 50522:2022.
Why should you use BS EN 50522 - Earthing of power installations?
BS EN 50522 ensures the safe and proper functioning of equipment.
What’s new about BS EN 50522:2022?
This is a technical revision of BS EN 50522:2010. The major changes in BS EN 50522:2022 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