Connection and Use of System Code (CUSC)

The Connection and Use of System Code (CUSC) constitutes the contractual framework for connection to, and use of, the national electricity transmission system.

The methodologies used to derive the charges that National Grid Electricity Transmission levies for connection to and use of the national electricity transmission system are also set out in the CUSC.

If you wish to discuss whether you need to be a party to this code and how to become one, please contact National Grid Electricity Transmission plc.

Connection and Use of System Code Modifications

Our decisions on proposed changes to this code are included below.

Publications and updates

  • Published: 18th Sep 2017
  • Decisions
  • 1 Associated documents
We have approved this modification to the Connection and Use of System Code (CUSC).

  • Published: 15th Aug 2017
  • Decisions
  • 1 Associated documents
Authority decision to send back CMP268 final mod report.

  • Published: 26th Jul 2017
  • Decisions
  • 1 Associated documents
This letter confirms that we consider the modification proposal CMP282 should not be progressed on an urgent basis.

  • Published: 22nd Jun 2017
  • Decisions
  • 1 Associated documents
We have decided to direct the implementation of CMP264/265 WACM4. CMP269 and CMP270 are the consequential modifications for CMP264 and CMP265.

  • Published: 22nd Jun 2017
  • Decisions
  • 7 Associated documents
Following our March 2017 consultation on industry proposals CMP264 and CMP265 and our consideration of responses, we have decided to direct that WACM4 be implemented, from 1 April 2018. This document covers our assessment of the impact of those proposals...

  • Published: 20th Jun 2017
  • Decisions, Open letters and correspondence
  • 1 Associated documents
Following our March 2017 consultation on industry proposals CMP264 and CMP265 and our consideration of responses, we have decided to confirm our “minded to” position and direct that Workgroup Alternative CUSC Modification (WACM) 4 should be made.

  • Published: 4th May 2017
  • Decisions
  • 1 Associated documents
This letter confirms Ofgem's decision that CMP276 should not be progressed on an urgent basis.

  • Published: 15th Mar 2017
  • Open letters and correspondence, Reports and plans
  • 0 Associated documents
Supplementary modelling report and associated data for our CMP264/265 minded to decision and draft impact assessment. We also invite interested stakeholders to an optional and have extended the date for responses.

  • Published: 8th Mar 2017
  • Decisions
  • 1 Associated documents
We have approved this modification to the Connection and Use of System Code (CUSC).

  • Published: 1st Mar 2017
  • Closed: 18th Apr 2017
  • Consultations and responses
  • 4 Associated documents
Industry have raised CUSC modifications CMP264 and CMP265. This impact assessment covers those proposals and their 23 alternatives sets out our minded to decision. We have extended the date for responses to this consultation to 9am on 18 April 2017.

Pages