Codes Homepage
Welcome to Codes
We are the National Grid ESO Code Administrator, and we are here to support you in all areas of code modification and discussion.
We are administrators for the Connection and Use of System Code (CUSC), the Grid Code (GC), the System Operator – Transmission Owner Code (STC), and the Security & Quality of Supply Standard (SQSS).
That means we’re here to support those in the industry who want to propose changes, debate important issues and drive key outcomes in the code modification processes. So whether you’re new to the process, or experienced in the way it all works, we’ll help you get to the information you need.
Electricity Codes
The Connection and Use of System Code is the contractual framework for connecting to and using the National Electricity Transmission System (NETS).
The Grid Code is the technical code for connection and development of the National Electricity Transmission System (NETS).
The System Operator – Transmission Owner Code defines the relationship between the transmission system owners and the system operator.
The Security and Quality of Supply Standard set out the criteria and methodology for planning and operating the National Electricity Transmission System.
The rules and governance arrangements for electricity balancing and settlement in Great Britain.
European network codes cover grid connections, markets, and system operation, providing a sustainable, secure, and competitive electricity market across Europe.
Code Panels
Everything you need to know about our four code Panels, including meeting dates and documentation.
New to the site or need a refresher? We’ve got information to help get you started and guide you through the modifications processes.
Search for a Code Modification
You can find any current or concluded modifications here, using the mod’s name or ID. Selecting your modification from the dropdown list will take you to the modification page.
Modification Tracker
Our modification tracker gives you the very latest detail on current modifications for each of the four codes. It includes the purpose of the modification and the stakeholders it affects, as well as Panel comments on prioritisation and where it is in the review process.