Licensed electricity distribution businesses, or Distribution Network Operators (DNOs) in Great Britain, are obliged under Condition 21 of their licences to maintain a Distribution Code detailing the technical parameters and considerations relating to connection to, and use of, their electrical networks.


Electricity North West

Northern Powergrid

Scottish and Southern Electricity Networks

SP Energy Networks

UK Power Networks

Western Power Distribution


Eclipse Power Networks

Energetics Limited

ESP Utilities Group

GTC (comprising both ETCL and IPNL licences)

UK Power Distribution Limited

Energy Assets Networks Limited

Fulcrum Electricity Assets Limited

Harlaxton Energy Networks Limited

Leep Electricity Networks Limited

Murphy Power Distribution Limited

Utility Assets Limited

Vattenfall Networks Limited

The GB Distribution Code

All DNOs currently operate the same version of the Code, and the Code is maintained by the Distribution Code Review Panel. All modifications to the Code are approved by Ofgem.

Issue 33: Effective from 23 July 2018

The implementation of the EU Network Codes is creating a substantial amount of modifications to the GB documentation, and has resulted in the creation of two new Engineering Recommendations for the connection of generation to distribution networks, EREC G98 and G99.

These have recently (15 May) been approved by the Authority. In common with the modifications to the Grid Code approved at the same time, an erroneous implementation date of 17 May 2019 was used in the drafting. The correct date should be 27 April 2019. In approving ERECs G98 and G99 the Authority asked that this mistake was corrected.

In parallel with the development of EREC G98 and G99, modifications have recently been approved by the Authority that change the requirements for loss of mains protection fitted to distributed generation. These changes now need to be applied to G98 and G99.

A number of typographical errors have come to light in G98 and G99, all of which are inconsequential, but the opportunity can now be taken to correct them.

Click here to download a copy of Distribution Code Issue 33

Click on the relevant link for a copy of the revised EREC G98/1-1 (2018) or EREC G99/1-1 (2018)

Authority decision can be found here

For previous versions of the GB Distribution Code click here

Distribution Code User Guide

The guide gives a high level overview of the Distribution Code, and is aimed at anyone with an interest in the Distribution Code. It contains information about the regulatory structure in Great Britain and Europe and also provides a simple explanation of the various sections of the Distribution Code.

Click here to download the current version of the GB Distribution Code User Guide

Annex 1 and Annex 2 Documents

Some requirements of the Distribution Code are implemented through other industry documents. They are listed in Annex 1 of the Distribution Code, and are mostly Engineering Recommendations. These documents typically cover certain technical areas in detail, such as connection of generation, switchgear ratings and supply quality planning limits.

There are other industry documents which are not implemented via the Distribution Code, but do have a material impact on distribution network users. These are listed in Annex 2 of the Distribution Code.

Standards and other documents referenced in Annex 1 and Annex 2 of the Distribution Code are available for free and can be downloaded at the following link:

Click here for Annex 1 and Annex 2 documents

Standard Governance Procedure

DNOs or Users may bring proposals for modifications to Annex 1 Standards and Annex 2 Standards for consideration by the DCRP Panel. DNOs and Users bringing forward proposals for modifications to Annex 1 Standards and Annex 2 Standards shall set out in general terms the aims of their proposal and the likely impact, including costs.

Further information on how to submit a modification can be found here.

Useful Links

Association for Decentralised Energy (formerly the Combined Heat & Power Association)

Association of Meter Operators

Department for Business, Energy & Industrial Strategy (formerly DECC)

Energy UK

Major Energy Users’ Council

Meter Operation Code of Practice Agreement (MOCOPA)

Microgeneration Certification Scheme

National Grid

National Grid
The Grid Code


Renewable Energy Association

Renewable UK

Solar Trade Association

Sustainable Energy Association (formerly Mircropower Council)