BS 7671 Amendment 4: What It Means for Plug-In Solar
BS 7671 Amendment 4 is the 2026 update to the UK's wiring regulations that formally recognises plug-in solar kits within the electrical safety framework. It took effect on 15 April 2026, and after a six-month transition period ending 15 October 2026, all new electrical work must comply with its requirements.
This guide explains what changed, what it means for anyone buying or installing a plug-in solar kit, and where the boundaries lie between Amendment 4 and the separate BSI product standard still to come.
Quick answer
BS 7671 Amendment 4 is the UK wiring regulation that formally recognises plug-in solar. It took effect on 15 April 2026 and applies to all new electrical work after the transition ends 15 October 2026. It defines safe install rules — but does not certify products. That is the separate BSI product standard, expected summer 2026.
What Is BS 7671?
BS 7671, formally titled "Requirements for Electrical Installations," is the UK's national standard for electrical safety in buildings. Electricians call it "the Wiring Regs." It covers everything from socket heights to cable sizing to how different energy sources connect to your home's circuits.
The standard is published jointly by the Institution of Engineering and Technology (IET) and the British Standards Institution (BSI). The current edition is the 18th Edition (BS 7671:2018), which has been updated through a series of amendments since its original publication.
Amendment 4, published 15 April 2026, is the latest and most significant of these updates. It is sometimes called "the Orange Book" in the trade, replacing the previous "Brown Book" (BS 7671:2018+A2:2022+A3:2024).
What Did Amendment 4 Change for Plug-In Solar?
Amendment 4 is a broad update covering battery storage, Power over Ethernet, medical locations, and energy efficiency. But for plug-in solar buyers, three changes matter most.
Section 712
Solar PV installations - now recognises small-scale PV via a standard plug without a dedicated spur or MCS installer
Section 551
Generating sets - updated rules for bidirectional energy flow between your home and the grid
Anti-Islanding
Auto-disconnect if grid fails - already industry practice, now formally required in the wiring regs
Section 712: Solar PV Installations
Section 712 has been the home of solar PV requirements in BS 7671 for years. Previously, it assumed all solar installations would be hardwired on a dedicated circuit by a qualified electrician. Amendment 4 updates Section 712 to acknowledge that small-scale PV connected via a standard plug does not require a dedicated spur or an MCS-certified installer, provided the kit meets the forthcoming BSI product standard.
This is the single biggest regulatory shift for plug-in solar. Before April 2026, connecting a solar panel to a standard socket technically fell outside the wiring regulations' framework. Now it sits inside it.
Section 551: Generating Sets
Section 551 covers how generators (including solar inverters) connect to domestic circuits and operate in parallel with the grid supply. Amendment 4 redrafted Regulation 551.7.1 to add requirements for bidirectional energy flow - meaning electricity that can travel both into and out of your home.
A new provision (indent c) requires a suitable protective device where energy flow is bidirectional. Another provision (indent d) sets conditions on connecting a generation source to the load side of an RCD. These changes ensure that the wiring regulations properly account for a home that both draws from and feeds into the grid.
Anti-Islanding: Now a Formal Requirement
Anti-islanding means that if the grid goes down, your solar kit must automatically stop exporting electricity. This prevents live current from reaching power lines that engineers might be working on.
Anti-islanding was already industry practice and a requirement under the G98 connection process. Amendment 4 makes it a formal requirement within BS 7671 itself, removing any ambiguity.
What does Amendment 4 not do?
This is where much of the misinformation online comes from. Amendment 4 is a wiring standard. It sets rules for electrical installations. It does not do any of the following.
| What it DOES | What it does NOT do |
|---|---|
| ✓ Recognise plug-in solar in wiring regs | ✗ Certify any specific product |
| ✓ Require anti-islanding formally | ✗ Change feed-in tariff rules |
| ✓ Set bidirectional energy flow rules | ✗ Change rooftop solar rules |
| ✓ Update PV and generator sections | ✗ Override tenancy agreements |
| ✓ Create framework for no-electrician install | ✗ Remove the G98 notification requirement |
| ✗ Apply to rooftop solar (still needs MCS installer) |
It does not certify any specific product. That is the job of the BSI product standard, which is a separate document expected in July 2026. Amendment 4 creates the framework; the BSI standard defines which kits are approved to operate within it.
It does not change feed-in tariff rules. Export payments (via the Smart Export Guarantee) are governed by Ofgem, not by BS 7671.
It does not change rooftop solar rules. If you want a traditional rooftop solar installation (panels hardwired into your consumer unit), you still need an MCS-certified installer. Amendment 4 only recognises plug-in kits that meet the BSI product standard.
It does not override tenancy agreements. Your landlord's permission is a contractual matter, not an electrical safety matter. Even if a kit is fully BS 7671 compliant, you still need your landlord's agreement to install it if your tenancy requires it.
It does not remove the need for G98 notification. You must still notify your Distribution Network Operator (DNO) that you have connected a generator to their network.
What Must a Compliant Plug-In Solar Kit Do?
Based on the Amendment 4 framework and confirmed G98 requirements, a plug-in solar kit sold in the UK must meet these criteria.
Grid connection certification
Look for certification to EN 50549 - the European standard for small generators connecting to LV distribution networks, covering anti-islanding, voltage and frequency tolerances, and grid protection - or to the equivalent UK standard the BSI is expected to publish this summer. The UK-specific regulatory bar is G98 type-testing under the ENA's Engineering Recommendations.
Anti-islanding (auto-disconnect)
If the grid fails, the inverter must detect the loss of mains and disconnect within the timeframes specified in Engineering Recommendation G98. This is non-negotiable.
800W maximum AC output
The current expectation is 800W maximum AC output per domestic circuit. That's the line beyond which a dedicated installation, and an electrician, becomes required, and it ensures the generation does not overload a standard UK ring main or radial circuit protected by a 32A or 20A MCB. The BSI product standard is expected to confirm this limit when it publishes.
BS 1363 UK plug connection
The kit must connect via a standard UK 3-pin plug (BS 1363) - not a Schuko, Europlug, or generic IEC lead. This ensures the connection is fused at 13A and compatible with UK socket-outlets without adaptation. This is one of the specific things the BSI product standard is expected to nail down formally.
Do I Need an Electrician for Plug-In Solar?
This is the question that brought most people here, and the answer depends on what you are doing.
No Electrician Needed
If you are plugging a compliant kit (one that meets the BSI product standard, once published) into an existing socket on an existing circuit, you do not need an electrician. That is the entire point of the regulatory changes: to enable consumers to safely connect small-scale generation without professional installation.
This only applies if:
- The kit meets the BSI product standard (expected July 2026)
- You are using an existing socket-outlet
- Your existing circuit has adequate RCD protection (see below)
- The kit does not exceed 800W AC output
Yes, Electrician Needed
You will need a qualified electrician registered with a Competent Person Scheme (Part P) if any of the following apply:
- You want a new dedicated spur or radial circuit installed for your solar kit
- Your consumer unit needs upgrading (e.g., replacing an old Type AC RCD with a Type A)
- You want to add a new socket-outlet specifically for the solar kit
- You are making any modification to your home's fixed wiring
These are notifiable works under Part P of the Building Regulations. A Competent Person Scheme electrician (NICEIC, NAPIT, ELECSA, or similar) can self-certify the work.
Do I need to notify my DNO via G98?
G98 is Engineering Recommendation G98, published by the Energy Networks Association. It governs how small generators (up to 16A per phase, which is approximately 3.68kW on a single-phase supply) connect to the distribution network. An 800W plug-in solar kit sits comfortably within the G98 threshold.
How G98 Works for Plug-In Solar
G98 operates as a "Fit and Inform" process:
- You install the kit first. No permission needed in advance
- You notify your DNO after installation, within 28 days of commissioning
- Your DNO records your property as having a small generator on the network
This is a notification, not an application. You are informing the DNO that generation equipment is now connected to their network.
Who Submits the G98 Notification?
The notification can be submitted by the manufacturer, the installer, or the homeowner. For plug-in solar kits, good manufacturers handle this for you as part of the purchase or registration process.
If a kit does not offer to handle G98 notification on your behalf, treat that as a red flag. It suggests the manufacturer has not fully thought through UK regulatory compliance.
What Information Is Needed?
- Your address and MPAN (meter point administration number, found on your electricity bill)
- The make and model of the inverter
- The rated output in kW
- Confirmation the equipment is type-tested to the relevant standards
- Date of commissioning
G98 Fast Track: Since 800W is well below the 3.68kW threshold, plug-in solar kits always qualify for Fast Track. You would only need the more complex G99 application process if your total generation exceeded 3.68kW.
RCD Requirements: Is Your Home Compatible?
An RCD (Residual Current Device) detects faults where current leaks to earth and disconnects the circuit in milliseconds. They are critical safety devices, and their type matters for plug-in solar compatibility.
Type A RCD (post-2015)
Compatible - no action needed. Detects both AC and pulsating DC fault currents. Found in most modern consumer units.
Type AC RCD (pre-2015)
Check and likely upgrade needed. Only detects AC fault currents. A DC fault from a solar inverter may not be detected. Upgrade typically costs £100-200.
Not sure?
Look at your consumer unit - the RCD type is printed on the front (sine wave for Type AC, sine wave plus pulsating DC symbol for Type A). Or ask an electrician to check for £50-80.
Amendment 4's updates to Section 551 include a provision (indent d) that addresses connecting generation sources to the load side of an RCD. The practical effect: if your kit is plugged into a circuit protected by an appropriate RCD (Type A or better), you meet the wiring regulations. If not, an electrician can upgrade your RCD relatively inexpensively.
What's the timeline for BS 7671 Amendment 4?
Understanding the sequence of events is critical because different rules apply at different stages.
What's the difference between Amendment 4 and the BSI product standard?
This distinction causes more confusion than anything else in the plug-in solar space. They are two completely separate documents doing different jobs.
BS 7671 Amendment 4 is a wiring standard. It tells electricians (and now consumers) how electrical equipment should be connected to a building's fixed wiring. It says: "A plug-in solar kit is allowed to connect via a standard socket, provided it meets certain conditions."
The BSI product standard (expected July 2026) is a product certification standard. It will tell manufacturers what their kit must do to be certified as safe for consumer self-connection. It will define testing requirements, labelling requirements, documentation requirements, and the specific technical criteria a kit must meet.
Think of it this way: Amendment 4 is like the Highway Code saying "electric scooters may use cycle lanes." The BSI product standard is like the vehicle certification that defines what qualifies as an approved electric scooter.
You need both. Amendment 4 without the BSI standard means the road exists but no vehicles are approved to drive on it. The BSI standard without Amendment 4 would mean approved vehicles with no road to drive on.
What myths exist about BS 7671 Amendment 4?
Because social media discussion around plug-in solar is fast-moving and often inaccurate, here are specific claims we see repeated that are either wrong or misleading.
Reality: Partially true but misleading. Amendment 4 created the wiring regulations framework. But until the BSI product standard publishes and certifies specific kits, the "plug in and go without an electrician" pathway is not fully operational. The legal status technically changed on 24 March 2026 when the government enacted the enabling legislation; Amendment 4 provides the technical framework.
Reality: Misleading. EN 50549 is the European standard for small generators connecting to LV distribution networks, and most quality microinverters carry it. But the UK-specific regulatory bar is G98 type-testing, and the formal product certification will be the BSI standard expected this summer. Treat EN 50549 as a strong indicator on your inverter - not a stand-alone UK approval.
Reality: Wrong. G98 notification to your DNO is required within 28 days of installation. This is not optional.
Reality: Not yet, and not automatically. The kit must meet the BSI product standard (once published) and the inverter must be G98 type-tested with anti-islanding. Simply attaching a UK plug to a generic inverter does not make it compliant.
What This Means If You Are Buying a Kit in 2026
If you are reading this during the transition period (April to October 2026), here is practical guidance.
Before the BSI product standard publishes (expected July 2026): Kits on sale are operating under CE/UKCA marking and manufacturer self-declaration. They are not yet certified to the BSI product standard because it does not exist yet. This does not necessarily mean they are unsafe, but it does mean the formal "no electrician needed" pathway is not yet confirmed for specific products.
After the BSI product standard publishes: Look for kits that explicitly state BSI product standard certification. These are the kits you can legally self-connect without an electrician. For a worked example of supermarket pricing once certified kits arrive, see our Lidl plug-in solar guide.
Regardless of timing, look for:
- G98 type-tested microinverter from a known manufacturer
- Built-in anti-islanding (automatic grid disconnection)
- 800W or lower AC output
- BS 1363 UK plug (not an adapter)
- G98 notification handling included
- Clear UK-specific documentation and support
The Five Things to Remember
- Amendment 4 is live. Published 15 April 2026. Creates the wiring regulations framework for plug-in solar. Mandatory for all new work from 15 October 2026.
- The BSI product standard is separate. Expected July 2026. This certifies specific kits. Without it, no kit is formally approved for consumer self-connection.
- No electrician needed for compliant kits on existing circuits. But only once a kit holds BSI product standard certification. Circuit modifications still require Part P.
- G98 notification is required. Notify your DNO within 28 days of installation. Good manufacturers handle this for you.
- Check your RCD. Type A (post-2015) is compatible. Type AC (pre-2015) may need upgrading.