Code of Practice for Electrical Energy Storage Systems, 4th Edition
This code of practice looks at electrical energy storage systems (EESS) applications and provides information for practitioners to safely and effectively specify, design, install, commission, operate and maintain a system.
It covers electrochemical energy storage systems in electrical installations, integration into low voltage power systems (AC and DC) and systems aligned with existing standards, regulations, and guidance. Its scope includes EESS intended for individual dwellings, commercial applications, including multi-occupancy buildings and multi-occupancy residential buildings, and industrial applications.
This fourth edition looks to bring the code of practice up to date with the latest developments in the electrical energy storage market and ensure alignment with Amendment 4 of BS 7671. Additions to the fourth edition include:
- Updated guidance and reference to other related standards
- New guidance on islanding equipment
- Expanded battery technology coverage including sodium-ion batteries
- New guidance for values of consumer earth electrode resistance
- Enhanced guidance on arc flash, fire safety, RCD selection, earthing, signage, and certification
This page is open to the public subject to the following terms:
- You may download the documents for your own use in reviewing content as part of the DPC process
- No further electronic copying is allowed without written permission
- You are permitted to share the URL of this page with other people to enable them to register their details to download and review the DPC documents
- You are not permitted to share a direct link to any of the DPC documents
- You are requested to return any comments using the DPC comment form provided
- The form should be electronically sent to the IET Codes and Guidance team at standardsandregulationsdpc@theiet.org.
Deadline for comments: 9am on Monday, 16 November 2026.