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
Modification status
ID Name Status Last Updated Sort ascending
GC0172 GC0172: Replacing References to Electricity Supply Industry Arbitration Association Current
GC0163 GC0163: GB Grid Forming (GBGF) - Removal of Virtual Impedance restriction Current
GC0164 GC0164: Simplification of Operating Code No.2 Current
GC0171 GC0171: Improving the clarity and transparency of the Compliance Process for Small Generators with a Bilateral Embedded Generator Agreement (BEGA) Current
Establishing ISOP in industry codes 2024 Establishing ISOP in industry codes 2024 Current
GC0159 GC0159: Introducing Competitively Appointed Transmission Owners Current
GC0169 GC0169: Material changes identified from Grid Code Modification GC0136 and Consistency of requirements between the Connection Conditions and European Connection Conditions Current
GC0166 GC0166: Introducing new Balancing Programme Parameters for Limited Duration Assets 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
GC0170 GC0170: Typographical and formatting updates following the implementation of GC0156: Facilitating the Implementation of the Electricity System Restoration Standard Implemented

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.