BS 7671 Amendment 4 Takes Over on 15 October, With a New Chapter on Home Batteries

The previous edition of the UK wiring regulations, BS 7671:2018+A3:2024, was withdrawn on 15 October. Amendment 4 (2026) now applies, and it adds a new chapter covering stationary batteries, including hybrid inverters and where a battery can be installed.

What changed

The IET and BSI published Amendment 4 on 15 April 2026, as BS 7671:2018+A4:2026, and said the older version would be withdrawn six months later. Electrical Contracting News gives that date as 15 October.

The amendment adds a chapter on stationary secondary batteries. According to the IET, it covers system design, power conversion equipment, bidirectional and hybrid inverters, and whether protective devices suit two-way power flow, which matters for vehicle-to-home setups. It also stresses battery location, ventilation and fire-risk reduction.

What we could not confirm

The standard itself is sold by the IET and BSI, and we have not read the full text of the new chapter. Several installer websites list specific placement rules, such as which rooms or spaces a battery may not go in. We could not check those against the standard, so we are not repeating them as fact.

The IET says BS 7671 applies to new installations, to additions and alterations, and to periodic inspection of existing installations. We could not confirm from its release how a system installed before 15 October is treated if it is later altered. Ask your installer rather than assuming.

What to ask your installer

If you are getting quotes now, ask which edition of BS 7671 the work will be certified to and how the installer's placement of the battery follows the new chapter. Ask for the certificate and the manufacturer's installation requirements in writing.

Our guides on where to put a home battery in the house and whether you can put one outside cover the practical side. For safety background, see are home batteries safe. This is general information, not electrical or legal advice.

Sources

• IET: IET and BSI officially publish Amendment 4 (2026) to BS 7671:2018
• Electrical Contracting News: IET & BSI officially publish Amendment 4

Related guides

Keep reading, or check your own numbers:

• Where to put a home battery in the house
• Can you put a home battery outside?
• DIY or professional installation for a home battery in the UK