Are you involved in the design, installation, or maintenance of earthing systems? Do you want to ensure the safety and reliability of your electrical installations? Then this blog is for you!
In this piece, we will explore the latest updates and revisions to the BS EN 50522:2022 standard. Highlighting the changes made to the standard and their implications for those involved in the design, installation, and maintenance of earthing systems.
What is BS EN 50522?
BS EN 50522 is the UK version of the European Standard that specifies the requirements for the design and installation of earthing systems in electrical installations exceeding 1 kV AC. It provides guidelines for the protection of people, equipment, and structures against electrical shocks and helps to ensure the reliable operation of electrical installations.
What does BS EN 50522 cover?
BS EN 50522 covers the following aspects related to earthing systems in electrical installations exceeding 1 kV AC:
- Design principles: The standard provides guidelines for designing earthing systems to ensure the safety of people and equipment in the event of electrical faults.
- Electrical safety: It covers the requirements for electrical safety, including earthing arrangements, protective bonding, and protection against electric shock.
- Testing and measurement: The standard includes guidance on testing and measurement techniques to ensure that the earthing systems are functioning correctly and meet the required safety standards.
- Compliance: BS EN 50522 highlights the relevant safety standards that earthing systems must comply with. Including those related to hazardous environments.
- Documentation: The standard outlines the documentation that should be produced during the design, installation, and maintenance of earthing systems. Including test reports and system schematics.
What’s new about BS EN 50522:2022?
BS EN 50522:2022 is the latest version of the European Standard that specifies the requirements for the design and installation of earthing systems in electrical installations exceeding 1 kV AC. Here are the key changes that the latest version of the standard includes:
- Text sections in italic which were indicating that the section is a copy of an IEC 61936-1 text replaced by reference note to IEC 61936-1 due to copyright reasons.
- Definitions in clause 3 updated, most notably touch voltages.
- Improved figures in Clause 3 for distribution of earth fault currents.
- Improvements to section 5.4 and Figure 9 to clarify the earthing design process. In addition when touch voltage assessments must be made.
- Rearranged Annex A and B including prospective permissible touch voltage and permissible step voltage.
- Introduction of stainless steel in Annex C and Annex D.
- More details and figures regarding fences in Annex G.
- Enlarged table of reduction factors and application on cables in Annex I.
- New figures in Annex J (J.4 and J.5) to assist in estimating the performance of earth electrodes.
- Details on soil resistivity measurements and touch voltage measurements including flow chart in Annex L.
- Clause 10 was Annex M in previous version. Bringing testing into the main body of the standard for the first time.
For UK users, the changes make little difference, as the national annexes remain unchanged. The guidance to use the IEC 60479-1:2005 5% body impedance curve from the HSE remains in place. Therefore, although touch voltage limits in the rest of Europe change somewhat. UK limits remain the same, and ENATS 41-24 provides a good set of limits applicable in most situations.
For European designers (in countries where A-deviations don’t apply), you get slightly different touch voltage limits, and stronger guidance to do testing as part of the commissioning process.
The data for stainless steel enables designers to integrate stainless steel LPS components into an HV earthing system. Therefore using components tested to the IEC 62561 (LPS components) series provides a greater guarantee of reliability compared to non-tested alternatives.
Unfortunately, the update does also mean that you need a copy of BS EN 61936-1 in your standards library as well. These sections have now been fully removed.
Missed our previous webinar?
Watch a replay here. This webinar is a bit more of a detailed dive into the updates and how they might affect your projects. Don’t miss this chance to discover the latest updates to this important standard and gain the knowledge and skills you need to ensure the safety and reliability of your electrical installations.
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