The Association of Manufacturers and suppliers of Power Systems and ancillary equipment

Connection to the network

Firstly, this document refers to connection to the Distribution Network, rather than the “Grid” or “National Grid”. This is because the majority of generation below 10 MW or so will be connected to the Distribution Network at 400 V or 11 000 V, rather than to the National Grid network in England and Wales, which operates at 275 kV or 400 kV.

The UK Distribution Code (DCode) stipulates requirements for the distribution-connection of embedded generators, also known as distributed generation. The DCode directs the Distribution Network Operator (DNO) to introduce these requirements which the DNO detail in Engineering Recommendations G59 and G83 (these being the most commonly encountered ERs).

For RIC engine driven generators, it is G59 which is the most likely rule set to be applied. G83 applies to generators of less than 13A per phase capacity and typically cover domestic solar PV or domestic stirling engine CHPs.

G59 is presently (January 2017) at revision status /3 (G59/3),

There is within the DCode a clause which allows a DNO to make a local decision regarding adherence to G59, and consequently a degree of ‘discussion and agreement’ exists around the G59 rule set and requirements which can be applied by an individual DNO for each and every step from proposal to sign-off for an embedded generator.

This is a specific document which provide guidance, clarity and aids dialogue with the relevant DNO for the connection of plant.

This is a document which is issued by the Energy Networks Association (ENA) entitled “Distributed Generation Connection Guide: A Guide for Connecting Generation that Falls Under G59 to the Distribution Network – April 2016”

G59 is presently being reviewed and harmonised with the recently released European Network Codes to ensure it will be appropriate for the networks of today and in the near future as the number of low inertia power generation scheme become predominant. The plan is that G83 And G59 will be updated and republished as G98 and G99 respectively. These new standards will apply from 2019. The following link will provide more information regarding the progress and developments of the European Network Code integration


Further reading and useful information follows:

ENA Engineering Documents such as G59, and G83 are available at a cost via the ENA web link –

Other useful references: -

ENA documents currently available that could be helpful to those involved with network connection of generating sets are:

ENA ER G83 - Recommendations for the Connection of Small-scale Embedded Generators (Up to 16A per Phase) in Parallel with Public Low-voltage Distribution Networks.

ENA ER G59 - Recommendations for the connection of embedded generating plant to the Public Electricity Suppliers distribution systems up to 20 kV or with outputs up to 5MW

ENA ER G75 - Recommendations for the connection of embedded generating plant to Public distribution systems above 20 kV or with outputs over 5 MW

Distribution Codes refer to

AMPS Web site FAQs

FAQ 1005;

Why is Loss of Mains detection required for embedded generators?

FAQ 1012;

What needs to be considered when nominating an embedded generator for Grid Code compliance applications?

FAQ 1009

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