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Introduction to the Document Catalogue

The Energy Networks Association (ENA) represents the interests of all energy companies in the UK. The Document Catalogue System is an online catalogue of engineering documents available from the ENA.

Documents available from the site include Technical Specifications, Engineering Recommendations and Reports, BEBS Specifications and reports supporting the electricity network process and policies.

Most documents are available to anybody but a small number are confidential to ENA member companies and can only be accessed by those member companies. The system allows clients that are not full ENA members to purchase documents by credit/debit card via secure transactions provided by WorldPay.

For more information, please click here to be routed to the ENA's corporate website or direct your query to:

Energy Networks Association Limited
4 More London Riverside
London SE1 2AU

Tel:  +44 (0)20 4599 7700
Email:  [email protected]

WARNING! Some of the older (pre 2003) documents available on this site were originally published by the now defunct Electricity Association. Please note that the ENA cannot take responsibility for the condition and content of these older documents and you are advised to seek advice before acting upon information held in them.

46 Documents Published Since Jan 2023

Type     Number     Issue No     Title     Published     Revision Due     Status     Price      
Engineering Technical Reports (ETR)001Issue 1 (New)

Generation Sharing Guidance

Oct 2024Q2 2025Current £Free Add to Order
Technical Specifications (TS)09-06Issue 10 (Revision)

Auxiliary multicore and multipair cables

Jul 2024Q1 2029Current £105.00 Add to Order
Technical Specifications (TS)43-14Issue 4 (Revision)

Insulated Aerial Bundled Conductors For Low Voltage Overhead Distribution Systems – Conductor Fittings and Associated Apparatus

Jul 2024Q1 2034Current £80.00 Add to Order
Technical Specifications (TS)43-15Issue 4 (Revision)

Insulator Binds and Equivalent Helical Fittings for Overhead Lines

Jul 2024Q2 2029Current £80.00 Add to Order
Technical Specifications (TS)35-3Issue 3 (Revision)

Continuous Maximum Rated (CMR) system transformers (for use on systems up to 132 kV)

May 2024Q1 2029Current £105.00 Add to Order
Technical Specifications (TS)35-7Issue 3 (Revision)

Tap-changers for system voltages up to and including 132kV

May 2024Q4 2029Current £80.00 Add to Order
Engineering Reports (EREP)G98/99Issue 1 (New)

Distributed Generation Connection Guide: G98 & G99

Mar 2024Q1 2025Current £Free Add to Order
Technical Specifications (TS)09-11Issue 3 (Revision)

Low voltage heat-shrinkable material components for use up to and including 600/1 000 V

2024 Current £80.00 Add to Order
Engineering Reports (EREP)144Issue 1 (New)

DNO Common Network Asset Indices Methodology V2.1: Health & Criticality

2024Q4 2028Current £Free Add to Order
Engineering Reports (EREP)145Issue 1 (New)

Good Practice Guide to DNO Common Network Asset Indices Methodology V2.1
 

2024Q4 2028Current £Free Add to Order
Engineering Reports (EREP)146Issue 1 (New)

DNO CNAIM V2.0: Methodology Changes Explained

2024Q4 2028Current £Free Add to Order
Technical Specifications (TS)35-2Issue 7 (Revision)

Emergency rated system transformers 66/20.5 kV, 66/11.5 kV and 33/11.5 kV delta/star and star/star connected

2024 Current £105.00 Add to Order
Technical Specifications (TS)41-18Issue 3 (Revision)

Partial discharge testing of bushings, capacitors, instrument transformers and switchgear of rated voltage 7.2 - 420 kV inclusive

2024Q1 2030Current £45.00 Add to Order
Technical Specifications (TS)43-103Issue 4 (Revision)

Low voltage overhead line shrouding materials

2024 Current £80.00 Add to Order
Technical Specifications (TS)43-13Issue 4 (Revision)

Aerial Bundled Conductors Insulated with Cross-Linked Polyethylene for Low Voltage Overhead Distribution

2024 Current £20.00 Add to Order
Technical Specifications (TS)48-2Issue 3 (Revision)

Fault Passage Indicators up to 132kV for Underground and Overhead Distribution Systems

2024 Current £65.00 Add to Order
Engineering Recommendations (EREC)G38Issue 2 (Revision)

Operational procedure associated with electricity supplies for traction purposes on AC and DC electrified lines

2024 Current £65.00 Add to Order
Engineering Recommendations (EREC)G44Issue 4 (Revision)

Code of practice for the coordination of power line carrier system frequencies in the range 30•0 kHz to 526•5 kHz

2024 Current £55.00 Add to Order
Engineering Recommendations (EREC)G59/3/8Issue 3 (Revision)

Issue 3 - Amendment 8

Recommendations for the Connection of Generating Plant to the Distribution Systems of Licensed Distribution Network Operators

2024 Current £Free Add to Order
Engineering Recommendations (EREC)G80Issue 4 (Revision)

Recommendations for the safe working of utilities’ staff and other parties near light rapid transit systems

2024 Current £55.00 Add to Order
Engineering Recommendations (EREC)G99 A10Issue 1 (New)

Issue 1 – Amendment 10

Requirements for the connection of generation equipment in parallel with public distribution networks on or after 27 April 2019

2024 Current £Free Add to Order
Engineering Recommendations (EREC)G99 NIIssue 1 (New)

Engineering Recommendation G99/NI Issue 1 – Amendment 1
7 December 2023
Requirements for the connection of generation equipment in parallel with public distribution networks in Northern Ireland on or after 27 April 2019
 

Dec 2023Q4 2028Current £Free Add to Order
Engineering Recommendations (EREC)G100 A2Issue 2 (Revision)

Technical Requirements for Customers’ Export and Import Limitation Schemes

Apr 2023 Current £Free Add to Order
Technical Specifications (TS)43-40Issue 4 (Revision)

Specification for single circuit overhead pole lines for use at high voltage up to and including 33 kV

Mar 2023 Current £185.00 Add to Order
Engineering Reports (EREP)130Issue 4 (Revision)

Guidance on the application of Engineering Recommendation P2, Security of Supply

Feb 2023 Current £Free Add to Order
Engineering Recommendations (EREC)P2Issue 8 (Revision)

Security of Supply

Feb 2023 Current £Free Add to Order
Technical Specifications (TS)98-1Issue 3 (Revision)

Environmental classification and corrosion protection of structures, plant and equipment

Jan 2023 Current £55.00 Add to Order
Engineering Recommendations (EREC)L9 - A1Issue 4 (Revision)

Structural testing of wood poles prior to climbing or use as a personal support

Jan 2023 Current £30.00 Add to Order
Technical Specifications (TS)09-16Issue 4 (Revision)

Tests on power cables with XLPE insulation and metallic sheath and their accessories, for rated voltages of 66 kV (Um = 72.5 kV), 110 kV (Um 123 kV) and 132 kV (Um = 145 kV)

2023 Current £45.00 Add to Order
Engineering Reports (EREP)141Issue 1 (New)

Guidance on Neutral Current Diversion

2023 Current £Free Add to Order
Technical Specifications (TS)18Issue 3 (Revision)

Partial discharge testing of bushings, capacitors, instrument transformers and switchgear of rated voltage 7.2 - 420 kV inclusive

2023Q1 2030Current £45.00 Add to Order
Technical Specifications (TS)37-1Issue 4 (Revision)

400 V a.c. switchgear, controlgear and fusegear assemblies

2023 Current £90.00 Add to Order
Technical Specifications (TS)37-2Issue 6 (Revision)

Public Electricity Network Distribution Assemblies

2023 Current £90.00 Add to Order
Technical Specifications (TS)41-45Issue 1 (New)

Outdoor, free standing CTs & VTs up to 36 kV

2023 Current £45.00 Add to Order
Technical Specifications (TS)43-119Issue 3 (Revision)

Design and use of temporary scaffold guards and conductor support systems

2023 Current £55.00 Add to Order
Technical Specifications (TS)43-12Issue 3 (Revision)

Insulated Aerial Bundled Conductors for Low Voltage Overhead Distribution Systems – Erection Requirements

2023 Current £185.00 Add to Order
Technical Specifications (TS)43-122Issue 2 (Revision)

Covered-conductors for overhead lines (having rated Voltages Uo/U greater than 0.6/1 kV up to and including 19/ 33 kV)

2023 Current £55.00 Add to Order
Technical Specifications (TS)43-91Issue 7 (Revision)

Stay strands and stay fittings for overhead lines

2023 Current £80.00 Add to Order
Technical Specifications (TS)43-94Issue 7 (Revision)

Earth rods and their connectors

2023 Current £55.00 Add to Order
Technical Specifications (TS)48-5Issue 5 (Revision)

Environmental test requirements for protection and control equipment and systems

2023 Current £55.00 Add to Order
Technical Specifications (TS)50-18Issue 5 (Revision)

Application of ancillary electrical equipment

2023 Current £65.00 Add to Order
Technical Specifications (TS)50-19Issue 3 (Revision)

Standard numbering for small wiring (for switchgear and transformers together with their associated relay panels)

2023 Current £45.00 Add to Order
Engineering Recommendations (EREC)G100 SummaryIssue 1 (New)

Engineering Recommendation G100 Issue 2 Overview and Summary Guide

2023 Current £Free Add to Order
Engineering Recommendations (EREC)G12Issue 5 (Revision)

Requirements for the Application of Protective Multiple Earthing to Low Voltage Networks

2023 Current £Free Add to Order
Engineering Recommendations (EREC)G28Issue 7 (Revision)

National Equipment Defect Reporting Scheme (NEDeRS®) – Notes of guidance

2023 Current £45.00 Add to Order
Engineering Recommendations (EREC)L38Issue 4 (Revision)

Overhead line conductors - protection against corrosion by the application of anti-corrosion grease during manufacture

2023 Current £65.00 Add to Order

30 Documents Under Revision

Type     Number     Issue No     Title     Published     Revision Due     Status     Price      
Technical Specifications (TS)26-01Issue 2 (Revision)

Insulating foam-filled tube and solid rod for live working

1977Q1 2021Current (Under Revision) £55.00 Add to Order
Technical Specifications (TS)43-91Issue 6 (Revision)

Stay strands and stay fittings for overhead lines

Dec 2016Q1 2022Current (Under Revision) £80.00 Add to Order
Engineering Recommendations (EREC)L38Issue 3 (Revision)

Overhead line conductors - protection against corrosion by the application of anti-corrosion grease during manufacture

Dec 2016Q1 2022Current (Under Revision) £65.00 Add to Order
Engineering Recommendations (EREC)C135Issue 1 (New)

Guidance for the operation and management of fluid filled cables. This document replaces ETR 135.

Nov 2016Q1 2022Current (Under Revision) £90.00 Add to Order
Technical Specifications (TS)9-9Issue 7 (Revision)

Distribution cables of rated voltage 0.6/1/ (1.2) kV with XLPE insulation, concentric waveform copper wire and solid aluminium conductors

Feb 2016Q1 2022Current (Under Revision) £45.00 Add to Order
Technical Specifications (TS)43-119Issue 2 (Revision)

Design and use of temporary scaffold guards and conductor support systems

Feb 2016Q1 2022Current (Under Revision) £55.00 Add to Order
Technical Specifications (TS)48-5Issue 4 (Revision)

Environmental test requirements for protection and control equipment and systems

2016Q1 2022Current (Under Revision) £55.00 Add to Order
Engineering Recommendations (EREC)G87Issue 2 (Revision)

Guidelines for the Provision of Low Voltage Connections to Multiple Occupancy Buildings

Jul 2015Q1 2022Current (Under Revision) £Free Add to Order
Technical Specifications (TS)41-37 Part 5Issue 1 (New)

Switchgear for use on 66 kV to 132 kV distribution systems Part 5 Inductive voltage transformers, capacitor voltage transformers, combined unit transformers and current transformers for use on 72.5 kV to 145 kV distribution systems

2015Q1 2022Current (Under Revision) £55.00 Add to Order
Technical Specifications (TS)41-37 Part 4Issue 2 (Revision)

Switchgear for use on 66 kV to 132 kV distribution systems (Disconnectors and earthing switches)

2015Q1 2022Current (Under Revision) £65.00 Add to Order
Engineering Recommendations (EREC)C46Issue 2 (Revision)

Measures necessary to minimise corrosion damage to buried metallic structures by neighbouring cathodic protection installations

Dec 2014Q1 2022Current (Under Revision) £65.00 Add to Order
Technical Specifications (TS)41-38Issue 1 (New)

Power installations exceeding 1 kV a.c. – Design of high-voltage open-terminal stations

2014Q1 2022Current (Under Revision) £65.00 Add to Order
Technical Specifications (TS)43-13Issue 3 (Revision)

Aerial bundled conductors insulated with cross-linked polyethylene for low voltage overhead distribution

2013Q1 2022Current (Under Revision) £20.00 Add to Order
Technical Specifications (TS)43-121Issue 1 (New)

Specification for single circuit overhead lines of compact covered construction on wood poles for use at high voltage up to and including 33 kV

Mar 2004Q1 2022Current (Under Revision) £110.00 Add to Order
Technical Specifications (TS)43-122Issue 1 (New)

XLPE covered-conductors for overhead lines (having rated voltages Uo/U greater than 0.6/1 kV up to and including 19/33 kV)

Mar 2002Q1 2022Current (Under Revision) £55.00 Add to Order
Engineering Recommendations (EREC)L9/3Issue 1 (New)

Structural testing of wood poles prior to climbing or use as a personal support

1995Q1 2022Current (Under Revision) £30.00 Add to Order
Technical Specifications (TS)9-17Issue 2 (Revision)

Single core cables for use in substations having extruded insulation and rated voltages of 6350/11 000 volts, and 19 000/33 000 volts

Jan 1991Q1 2022Current (Under Revision) £80.00 Add to Order
Engineering Recommendations (EREC)C93Issue 1 (New)

Type approval tests for mechanical connections to metallic sheaths of cables Addendu

1989Q1 2022Current (Under Revision) £65.00 Add to Order
Technical Specifications (TS)35-1 Part 4Issue 6 (Revision)

Distribution transformers - Part 4 Pole mounted transformers

2014Q3 2022Current (Under Revision) £55.00 Add to Order
Technical Specifications (TS)98-1Issue 2 (Revision)

Environmental classification and corrosion protection of structures, plant and equipment

2014Q4 2022Current (Under Revision) £55.00 Add to Order
Technical Specifications (TS)43-120Issue 2 (Revision)

Fittings for covered conductors for overhead lines (having rated voltages U0/U greater than 0.6/1 kV up to and including 19/33 kV)

Dec 2012Q1 2024Current (Under Revision) £80.00 Add to Order
Technical Specifications (TS)41-21Issue 2 (Revision)

Portable earthing equipment for overhead lines and substations

Jan 2022Q1 2025Current (Under Revision) £65.00 Add to Order
Technical Specifications (TS)41-36Issue 3 (Revision)

Switchgear for service up to 36 kV (Cable and Overhead conductor connected)

2012Q3 2025Current (Under Revision) £285.00 Add to Order
Engineering Recommendations (EREC)P18Issue 2 (Revision)

Complexity of Distribution Circuits Operated at or above 22kV

2022 Current (Under Revision) £Free Add to Order
Technical Specifications (TS)43-50Issue 3 (Revision)

Specification for single circuit overhead lines on wood poles for use at 132kV

2022 Current (Under Revision) £65.00 Add to Order
Engineering Technical Reports (ETR)122Issue 1 (New)

Guide to the application of Engineering Recommendation G5/4 in the assessment of harmonic voltage distortion and connection of non-linear equipment to the electricity supply system in the U.K

Dec 2002 Current (Under Revision) £185.00 Add to Order
Engineering Technical Reports (ETR)120Issue 1 (New)

Calculation of fault currents in three-phase AC power systems (Application Guide to Engineering Recommendation G74)

1995 Current (Under Revision) £185.00 Add to Order
Engineering Recommendations (EREC)P29Issue 1 (New)Planning limits for voltage unbalance in the UK for 132 kV and below1990 Current (Under Revision) £Free Add to Order
Engineering Recommendations (EREC)G38Issue 1 (New)

Operational procedure associated with electricity supplies for traction purposes on AC and DC electrified lines

1985 Current (Under Revision) £65.00 Add to Order
Engineering Recommendations (EREC)P24Issue 1 (New)AC traction supplies to British Rail1984 Current (Under Revision) £Free Add to Order

26 Distribution Code Documents

Type     Number     Issue No     Title     Published     Revision Due     Status     Price      
Engineering Reports (EREP)G98/99Issue 1 (New)

Distributed Generation Connection Guide: G98 & G99

Mar 2024Q1 2025Current £Free Add to Order
Engineering Recommendations (EREC)G59/3/8Issue 3 (Revision)

Issue 3 - Amendment 8

Recommendations for the Connection of Generating Plant to the Distribution Systems of Licensed Distribution Network Operators

2024 Current £Free Add to Order
Engineering Recommendations (EREC)G99 NIIssue 1 (New)

Engineering Recommendation G99/NI Issue 1 – Amendment 1
7 December 2023
Requirements for the connection of generation equipment in parallel with public distribution networks in Northern Ireland on or after 27 April 2019
 

Dec 2023Q4 2028Current £Free Add to Order
Engineering Reports (EREP)130Issue 4 (Revision)

Guidance on the application of Engineering Recommendation P2, Security of Supply

Feb 2023 Current £Free Add to Order
Engineering Recommendations (EREC)P2Issue 8 (Revision)

Security of Supply

Feb 2023 Current £Free Add to Order
Engineering Recommendations (EREC)G12Issue 5 (Revision)

Requirements for the Application of Protective Multiple Earthing to Low Voltage Networks

2023 Current £Free Add to Order
Engineering Reports (EREP)131Issue 3 (Revision)

Analysis package for assessing the security contribution from distributed generation and electricity storage systems – Users’ guide

Jun 2020Q2 2025Current £Free Add to Order
Engineering Reports (EREP)131 AttachIssue 3 (Revision)

Analysis Package For Assessing Generation Security Capability - Users' Guide

Jun 2020Q2 2025Current £Free Add to Order
Engineering Recommendations (EREC)G5Issue 5 (Revision)

Harmonic voltage distortion and the connection of harmonic sources and/or resonant plant to transmission systems and distribution networks in the United Kingdom

Jun 2020Q2 2025Current £Free Add to Order
Engineering Recommendations (EREC)G5Issue 5 (Revision)

Harmonic voltage distortion and the connection of harmonic sources and/or resonant plant to transmission systems and distribution networks in the United Kingdom

Dec 2019Q4 2024Current £Free Not Available
Engineering Recommendations (EREC)G83Issue 2 (Revision)

Issue 2 Amendment 3 
Recommendations for the Connection of Type Tested Small-scale Embedded Generators (Up to 16A per Phase) in Parallel with Low-Voltage Distribution Systems

Jun 2019Q2 2024Current £Free Add to Order
Engineering Recommendations (EREC)G99Issue 1 (New)

Issue 1 Amendment 4 
Requirements for the connection of generation equipment in parallel with public distribution networks on or after 27 April 2019

Jun 2019Q2 2024Current £Free Add to Order
Engineering Recommendations (EREC)P28Issue 2 (Revision)

Voltage fluctuations and the connection of disturbing equipment to transmission systems and distribution networks in the United Kingdom

May 2019 Current £Free Add to Order
Technical Specifications (TS)41-24Issue 2 (Revision)

Guidelines for the design, installation, testing and maintenance of main earthing systems in substations

Nov 2018Q4 2023Current £Free Add to Order
Engineering Recommendations (EREC)S34Issue 2 (Revision)

A guide for assessing the rise of earth potential at electrical installations

Nov 2018Q4 2023Current £Free Add to Order
Engineering Recommendations (EREC)P25Issue 2 (Revision)The short-circuit characteristics of single-phase and three-phase low voltage distribution networks2018Q1 2023Current £Free Add to Order
Engineering Recommendations (EREC)G81 Part 1Issue 3 (Revision)

Framework for new low voltage housing development installations - Part 1 Design and planning

2016Q1 2023Current £Free Add to Order
Engineering Recommendations (EREC)G81 Part 2Issue 2 (Revision)

Framework for new low voltage housing development installations - Part 2 Materials specification

2016Q1 2023Current £Free Add to Order
Engineering Recommendations (EREC)G81 Part 3Issue 2 (Revision)

Framework for new low voltage housing development installations - Part 3 Installation and records

2016Q1 2023Current £Free Add to Order
Engineering Recommendations (EREC)G81 Part 4Issue 3 (Revision)

Framework for new industrial and commercial underground connections - Part 4 Design and planning

2016Q1 2023Current £Free Add to Order
Engineering Recommendations (EREC)G81 Part 5Issue 2 (Revision)

Framework for new industrial and commercial underground connections - Part 5 Materials specification

2016Q1 2023Current £Free Add to Order
Engineering Recommendations (EREC)G81 Part 6Issue 2 (Revision)

Framework for new industrial and commercial underground connections - Part 6 Installation and records

2016Q1 2023Current £Free Add to Order
Engineering Recommendations (EREC)G81 Part 7Issue 2 (Revision)

Framework for contestable diversionary and reinforcement works not exceeding 33 kV - Part 7 Contestable diversionary and reinforcement works

2016Q1 2023Current £Free Add to Order
Engineering Recommendations (EREC)G87Issue 2 (Revision)

Guidelines for the Provision of Low Voltage Connections to Multiple Occupancy Buildings

Jul 2015Q1 2022Current (Under Revision) £Free Add to Order
Engineering Recommendations (EREC)P29Issue 1 (New)Planning limits for voltage unbalance in the UK for 132 kV and below1990 Current (Under Revision) £Free Add to Order
Engineering Recommendations (EREC)P24Issue 1 (New)AC traction supplies to British Rail1984 Current (Under Revision) £Free Add to Order