GB/T 40661-2021

This standard specifies the calibration methods, procedures, and requirements for instruments that measure power frequency magnetic fields, typically at 50 Hz or 60 Hz. It is applied in metrology laboratories and by calibration service providers to ensure the accuracy and traceability of magnetic field meters used in industrial environments, such as near power transmission lines, substations, and electrical equipment. The standard is essential for compliance with electromagnetic field exposure limits and for quality assurance in electrical engineering and occupational safety testing.