BS 7671 is the UK’s standard for electrical installations, often called the Wiring Regulations. Every new circuit, consumer unit or rewire should be designed, installed and tested to it. In 2026, the standard was updated again with Amendment 4 to the 18th Edition, known as BS 7671:2018+A4:2026.
If you own a home, let a property or run a business, here is what has changed and what it means for you.
When did Amendment 4 come in?
Amendment 4 was published on 15 April 2026. For six months, electricians could work to either the previous version (Amendment 3) or the new one. That overlap ended on 15 October 2026, and Amendment 4 now applies to all new electrical work.
What has changed?
Much of Amendment 4 is about the technology now arriving in homes and workplaces. The main additions include:
- Home battery storage. There are new requirements for stationary batteries, covering isolation, earthing, ventilation, labelling and where batteries can be located. Unsuitable locations, such as escape routes and lofts, are ruled out.
- Generators. Updated rules for low-voltage generators, including standby generators, cover safe changeover and stopping power from feeding back into the supply.
- Power over Ethernet (PoE). New guidance covers systems that send low-voltage power through data cables, such as some CCTV cameras, Wi-Fi access points and smart lighting.
- Functional earthing for IT equipment. The rules make clearer how earthing for data and communications equipment must sit alongside the protective earthing that keeps people safe.
- Energy efficiency. The guidance on designing more efficient installations has been updated. It is still advice rather than a requirement.
What does this mean for homeowners?
For most homes, Amendment 4 won’t change anything straight away. The wiring regulations aren’t retrospective, so an installation that met the rules when it was put in isn’t automatically unsafe because the standard has moved on.
Where it matters is if you’re planning new work, especially home battery storage or a standby generator. Any new installation should now be designed and installed to Amendment 4, so it’s worth checking that your electrician is working to the current edition.
What does this mean for landlords?
Private landlords in England already need an Electrical Installation Condition Report (EICR) at least every five years. Social landlords now have the same duty: the transitional deadline for checking existing social tenancies was 1 November 2026.
An EICR assesses the condition of an installation and highlights anything dangerous or needing improvement. If your property has newer technology, such as battery storage, your electrician will also look at how it has been installed against the current rules.
What does this mean for businesses?
Offices, shops and commercial premises are taking on more of the technology covered by Amendment 4, from PoE-powered cameras and access points to backup generators and on-site batteries. If you’re planning an office fit-out, a refurbishment or new IT and security systems, the electrical design should follow Amendment 4.
Do I need to do anything now?
In most cases, no. But it’s a good time to:
- Check when your last EICR was carried out, especially if you’re a landlord or business.
- Use a registered electrician for new work, so it is designed, installed and certified to the current regulations.
- Plan ahead if you’re adding battery storage, a generator or new network equipment, because these are the areas where the rules have changed most.
Frequently asked questions
Is my existing wiring illegal now that Amendment 4 is in force?
No. BS 7671 isn’t retrospective. An installation that met the regulations when it was put in isn’t automatically non-compliant because a newer amendment has been published. Amendment 4 applies to new work. An EICR will highlight anything in an existing installation that is dangerous or needs improvement.
When did BS 7671 Amendment 4 become mandatory?
Amendment 4 was published on 15 April 2026. From then until 15 October 2026, electricians could work to either Amendment 3 or Amendment 4. Since 15 October 2026, all new electrical work should be designed and installed to Amendment 4.
Does Amendment 4 affect home battery storage?
Yes. Battery storage is one of the main areas covered. Amendment 4 adds requirements for stationary batteries, including isolation, earthing, ventilation, labelling and suitable locations. If you’re planning a home battery, make sure the installer works to the current regulations.
Need advice?
Urgent Electrical Services is an NICEIC-approved contractor serving Nottingham and the East Midlands. If you’re planning new electrical work or need an inspection, get in touch and we’ll explain what the current regulations mean for your property.
