IEC 62271-208:2025

Overview

IEC 62271-208:2025 sets out practical methods for the evaluation and documentation of steady-state, power-frequency electromagnetic fields (EMF) generated by high-voltage (HV) switchgear and controlgear assemblies, as well as HV/LV prefabricated substations. Relevant for equipment rated above 1 kV and up to and including 52 kV, the standard provides essential guidance for both manufacturers and users who need to assess and compare the electromagnetic field characteristics of such electrical equipment. IEC 62271-208:2025 covers the measurement and calculation of both electric and magnetic fields in the frequency range from 15 Hz to 60 Hz, using procedures suitable for factory, laboratory, and - where practical - on-site evaluation.

Key Topics

• Scope and Applicability: The document addresses HV switchgear assemblies (per IEC 62271-200 and IEC 62271-201) and HV/LV prefabricated substations (per IEC 62271-202) within the indicated voltage and frequency ranges.
• Measurement and Calculation Methods: Summarizes requirements and presents procedures for quantifying steady-state, power-frequency electric and magnetic fields using either direct measurement or analytical calculation.
• Evaluation under Defined Conditions: Specifies that evaluation should occur under controlled conditions simulating operational maximums and considers influencing factors such as equipment configuration and current loadings.
• Hot Spot and Isoline Procedures: Details two primary measurement procedures:
  • Hot spot method: Identifies local maxima of field values on measurement surfaces.
  • Isoline method: Maps lines of constant field strength across a measurement plane.
• Documentation and Reporting: Outlines how to record, process, and present EMF evaluation data for compliance and comparison.
• Exclusions: The standard does not specify limits for electromagnetic fields or methods for assessing human exposure.

Applications

IEC 62271-208:2025 is valuable for stakeholders who need to:

• Plan and Install HV Equipment: Provides the methodology to assess potential electromagnetic fields before installing switchgear and substations, supporting informed site planning and layout optimization to minimize unwanted EMF.
• Product Comparison and Selection: Enables comparison of different switchgear and substation products based on quantified EMF characteristics, an important factor in procurement and equipment specification.
• Regulatory Compliance: Supports documentation efforts to demonstrate due diligence with respect to local or international guidelines about electromagnetic fields, in collaboration with standards such as IEC 61786-1 and IEC 61786-2.
• Quality Assurance and Factory Testing: Ensures reproducible and comparable EMF measurement results during factory acceptance tests or type testing in laboratory environments.
• Verification through Calculation: Where measurement is impractical, rigorous calculation methods can be used as outlined, ensuring flexibility in application.

Related Standards

• IEC 62271-200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV.
• IEC 62271-201: AC solid-insulation-enclosed switchgear and controlgear for similar voltage ranges.
• IEC 62271-202: AC prefabricated substations for voltages above 1 kV and up to and including 52 kV.
• IEC 61786-1 and IEC 61786-2: General requirements and basic measurement standards for low-frequency electromagnetic fields related to human exposure.
• IEC 61000-6-2: Electromagnetic compatibility (EMC) - Immunity for industrial environments.

Practical Value

By adhering to IEC 62271-208:2025, manufacturers, utilities, and consultants gain a harmonized methodology to evaluate and document the EMF from HV infrastructure. This supports transparent communication with stakeholders, facilitates regulatory and internal compliance, and enables risk assessment regarding electromagnetic disturbances related to HV switchgear and substations. The standard fosters consistent, repeatable evaluation practices across the industry, making it essential for anyone involved with the specification, testing, or deployment of high-voltage electrical equipment.