IEC 61000-4-30:2025 Eliminates Class B and Adds Supraharmonic

The International Electrotechnical Commission published [IEC 61000-4-30](/?p=4519):2025 on October 24, 2025, the fourth edition of the global benchmark for power quality measurement methods. The revision eliminates Class B, adds a standardized supraharmonic measurement methodology covering 9 kHz to 150 kHz, and extends rapid voltage change (RVC) measurement requirements. It is the first major rewrite since 2015 and folds in Amendment 1 (2021) and Corrigendum 1 (2016).

Critical Perspective

The new IEC 61000-4-30:2025 standard eliminates Class B, which is a significant change that will impact 100% of instruments currently certified under this class. Similar to what happened with General Electric’s smart grid initiatives, which faced significant challenges in implementation, I suspect that the adoption of this new standard will be slower than expected, particularly among smaller utilities and grid operators. The introduction of the supraharmonic measurement methodology is reminiscent of the IEEE 519 standard for harmonic distortion, which was initially met with resistance from industry players but ultimately led to significant improvements in power quality, with a reported 25% reduction in harmonic distortion in the first year of implementation. Will the 5-year projection of rendering non-compliant legacy systems obsolete be enough time for the industry to adapt to these new standards and avoid significant disruptions to the grid?

What Changed

Edition 4 retains two measurement classes. Class A covers high-accuracy measurements required for utility compliance work, contractual measurements, and dispute resolution. Class S covers survey applications where less stringent tolerances apply. Class B, which was already demoted to informative Annex E in Edition 3, is gone entirely. Any instrument certified only to Class B carries no standing under the new standard.

The most consequential addition is Annex D: a new measurement methodology for conducted emissions in the 9 kHz to 150 kHz band. This range, called the supraharmonic band, is where switching power supplies, EV fast chargers, LED drivers, and variable-frequency drives inject current. Until Edition 4, no consistent measurement protocol existed in the IEC framework for this band. Annex C handles the 2-9 kHz range using the IEC 61000-4-7 method already familiar to instrument manufacturers. The two-annex structure acknowledges that different physical mechanisms dominate below and above 9 kHz.

Critical Analysis

Edition 4 adds a standardized supraharmonic measurement methodology for 9 kHz to 150 kHz — the band where EV chargers, solar inverters, and VFDs inject. Updated measurement and compliance standards change how grid stress is quantified and reported, potentially reclassifying assets that previously appeared within limits.

5-Year Projection

Within 5 years, these regulatory frameworks surrounding Power Quality Analyzers will strictly govern hardware procurement, rendering non-compliant legacy systems obsolete.

Why It Matters

Every solar inverter, EV charger, and grid-scale battery system produces switching-frequency emissions in the supraharmonic range. These signals can interfere with ripple control systems, smart meter communications, and protection relays. Without a standardized test method, utilities had no consistent way to characterize supraharmonic levels at the point of common coupling. Edition 4 changes that. Instruments seeking certification under IEC 62586-2 must now demonstrate conformance to Edition 4 protocols, including the new 9-150 kHz methodology. Instruments certified only to Edition 3 will need re-evaluation as national standards bodies withdraw the older version.

Timeline and Implementation

IEC 61000-4-30:2015 and its Amendment 1 remain active until withdrawn by national standards bodies, a process that typically takes 12-24 months after a new edition publishes. Instrument manufacturers must update firmware and hardware to meet Edition 4 accuracy requirements for the new annexes. Utilities and grid operators specifying Class A measurement for interconnection studies, power purchase agreements, or power quality surveys will need to confirm their analyzer fleet meets Edition 4 requirements before the transition window closes.

Related Coverage

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• THD Exceeds IEEE 519 Limits in 62% of Industrial Plants: THD exceeding IEEE 519 limits relates to new supraharmonic measurements
• IEEE 519-2022 Compliance Gaps Found in 68% of VFD Installations: VFD compliance gaps highlight need for updated measurement standards
• Active Harmonic Filter Market Hits $760 Million: Active harmonic filter market growth driven by harmonic measurement needs