On December 31,2025, the National Standardization Administration officially approved and promulgated the national standard GB/T 17625.8-2025, titled "Electromagnetic Compatibility – Limits – Part 8: Harmonic current limits for equipment connected to a public low-voltage system with a per-phase input current greater than 16 A but less than or equal to 75 A," developed by TC246 (National Technical Committee for Electromagnetic Compatibility Standardization). The standard came into effect on July 1, 2026, completely replacing the previous national standard GB/T 17625.8-2015.
Standard Content
This standard establishes stringent harmonic current emission limits for equipment with high rated currents (greater than 16 A and not exceeding 75 A per phase) connected to the public low-voltage grid, such as industrial machinery and large-scale air conditioning systems. It specifies absolute limits for harmonics from the second to the forty-first order and introduces an evaluation method based on the short-circuit ratio of the grid to which the equipment is connected, aiming to control harmonic pollution caused by these medium-to high-power devices on the power quality of the public grid.
The standard "Electromagnetic Compatibility – Limits – Part 8: Harmonic current limits for equipment connected to a common low-voltage system with a per-phase input current greater than 16 A and less than or equal to 75 A" (GB/T 17625.8-2025) applies to electrical and electronic equipment connected to such systems when their per-phase input current ranges between 16 A and 75 A. Its primary objective is to regulate harmonic current emissions from these devices, ensuring stable grid operation and power quality.
(1) Medium-power industrial equipment: including frequency converters, servo systems, and medium-frequency induction heating devices. These devices account for a significant proportion in industrial automation, and their nonlinear load characteristics result in substantial harmonic emissions.
(2) Commercial charging stations: With the widespread adoption of electric vehicles, charging stations, as high-power loads, may generate harmonic emissions that could compromise grid voltage quality.
(3) Other equipment: Including UPS power supplies, welding machines, etc., must comply with this standard provided they meet the input current requirements (16 A <I ≤ 75 A) and are connected to a public low-voltage system (e.g., 220 V/380 V grid).
GRGTEST-related Service Capabilities
GRGTEST has established a comprehensive testing capability system that fully complies with all standard requirements. It possesses a high-quality testing platform meeting these standards, including a dedicated test power supply capable of accurately simulating grid impedance and delivering stable high-power output with minimal waveform distortion. The company employs qualified operators who can safely operate the system under high-voltage and high-current conditions, correctly configure testing setups, process data, and generate professional test reports compliant with standards. Additionally, GRGTEST provides technical services such as correlation simulations and filter protection design solutions.