You can raise a modification – or mod – when you want to propose a change to any part of the Grid Code. 

For more information, please contact [email protected]

Search for any current or concluded modifications by name or ID. You can sort mods by ID, name, status or date of update. Or filter according to status.

Views reference
ID Name Status Last Updated Sort ascending
GC0164 GC0164: Simplification of Operating Code No.2 Current
GC0159 GC0159: Introducing Competitively Appointed Transmission Owners Current
GC0117 GC0117: Improving transparency and consistency of access arrangements across GB by the creation of a pan-GB commonality of Power Station requirements Current
GC0166 GC0166: Introducing new Balancing Programme Parameters for Limited Duration Assets Current
GC0156 GC0156: Facilitating the Implementation of the Electricity System Restoration Standard Current
GC0163 GC0163: GB Grid Forming (GBGF) - Removal of Virtual Impedance restriction Current
GC0167 GC0167: Material and Non Material Grid Code Changes Current
GC0162 GC0162: Changes to OC6 to amend the operational timings for the delivery of the additional demand reduction above 20%, with a focus between 20% and 40% Concluded
GC0154 GC0154: Incorporation of interconnector ramping requirements into the Grid Code as per SOGL Article 119 Current
GC0155 GC0155: Clarification of Fault Ride Through Technical Requirements Current

More about modifications

Modification Tracker

Our Tracker gives you the latest details on current code modifications including the purpose and the stakeholders it affects, as well as panel comments and where it is in the review process. It is published on the 7th (or next working day) of each month.

Modification Proposal Form

If you're thinking about raising a modification, please get in touch with us. Our experts can give you advice on your Proposal, explain how the modification process works and help to answer any questions you may have. When we receive your Proposal, we'll check it through and work together to make sure it's easy to understand.


Once you've been in touch and are ready to write your Proposal paper, send it to us by the monthly modification submission date which you can find on our Calendar.