Background
The stability date for the current 3rd edition, IEC 61400-2:2013, was extended to 2025-12-12 to allow various related work projects to complete and the results to be accessible for the revision (e.g., IEA Wind Task 41).
MT 2 therefore proposes to initiate the 4th revision of IEC 61400-2 to meet the current stability date.
MT2 kicked off the discussion of the revision on 2022-05-24 with plans to conclude by 2025 stability date. The table below shows the estimated timeline for the 4th revision, based on recommendations from the IEC TC 88 Secretary.

Target dates
CD 2023-06
CDV 2024-06
FDIS 2025-03
IS 2025-06

Scope
MT2 experts were surveying the scope of work for this revision. We have been holding monthly virtual meetings, discussing these items from high priority to low.
The third item from the top is a redefinition of the scope of IEC 61400, which currently applies to wind turbine with a rotor swept area up to 200 m2. The global small, distributed wind community has expressed a need to expand the scope of 61400-2 (e.g., IEA Wind Task 41). For this topic, we have been working on a list of turbines and plotting rated power versus rotor swept area to help inform the discussion and aid in understanding the impact(s) of a scope expansion.
MT2 experts and observers discussed the scope topic.
The outcome of the survey shows strong interest in MT 2 to expand the scope of 61400-2, possibly from the existing 200 m2 rotor swept area to approximately 1000 m2, thus capturing turbines in the ~100-kW range of rated power.
Currently, IEC 61400-1 contains a ‘medium wind’ annex applying to turbines with a rotor swept area of 200 m2 to 1000 m2. The scope expansion being deliberated in MT 2 would effectively fold this ‘medium wind’ category into the small wind turbine standard.
Note that MT 2 also intends to pursue a tiered approach for some requirements based on rotor swept area
and archetype (e.g., micro wind turbines will have requirements that differ from larger turbines, Horizontal Axis Wind Turbines (HAWTs) will have requirements that differ from Vertical Axis Wind Turbines (VAWTs), etc.

Action
P-members are requested to:
• comment on and approve the proposed scope of work for the 4th revision
Please provide your response using the IEC Comments Form and submit them using the IEC electronic voting / commenting system