UK Plug-in Solar Rules Confirmed: New Interim Specification Explained

The main UK plug-in solar product rules are no longer draft proposals. Alongside its consultation response, the Department for Energy Security and Net Zero has published Version 2.0 of the Plug-in Solar Device Interim Product Specification.

The new interim specification gives us the clearest picture yet of what UK launch kits and launch rules will look like. It confirms a consumer-installed product connected through a standard UK three-pin socket, with a maximum inverter output of 800VA - commonly described as 800W. It also allows up to 2,000W of solar-panel capacity within an approved kit, while excluding batteries and placing strict requirements on plugs, circuits, mounting, product documentation and registration.

There is still one crucial distinction: the interim specification has now been published, but the new legal route is not yet in force. The government must still complete the regulatory amendments and announce their commencement date before compliant plug-in solar kits can be legally sold and used through a household socket.

What has now been confirmed?

The government has published two important documents:

• its final response to the June 2026 plug-in solar consultation, explaining the policy decisions and changes made after stakeholder feedback; and
• Version 2.0 of the Plug-in Solar Device Interim Product Specification, setting out the technical, product and consumer-information requirements that launch products must meet.

This means we no longer need to infer the launch rules from the original consultation draft. The published interim specification now defines what a launch-ready compliant plug-in solar product looks like, how it must connect to a home, what information manufacturers must provide and which uses are prohibited.

The government received 466 consultation responses. Support was strong: 88% backed the proposed route using a standard BS 1363 plug, while 86% supported requiring compliance with the interim specification before a product is placed on the market.

The UK plug-in solar launch rules

Maximum output: 800VA through the household socket

A compliant plug-in solar inverter must have a maximum apparent power of no more than 800VA, with the current supplied to the household circuit limited to 3.5A.

For ordinary consumers this will normally be described as an 800W plug-in solar system. The important point is that the limit applies to the inverter's mains output, not necessarily to the combined rating printed on the solar panels.

Up to 2,000W of solar panels can feed the 800W inverter

The interim specification retains a maximum of 2,000W of total solar-panel capacity. It permits approved multi-component kits containing up to four panels, provided the inverter output remains capped at 800VA and the complete configuration meets the specification.

This means a compliant product could pair an 800W inverter with more than 800W of panels. For example, 1,200W or 1,600W of panel capacity could help the system reach its maximum output more often during weaker light, without allowing more than 800VA into the home.

There is an additional precaution for larger arrays: manufacturers must advise customers installing more than 960W of panel capacity to consider a professional assessment of their existing electrical installation before proceeding.

A standard UK plug, but not an ordinary appliance lead

Launch products will connect through a UK BS 1363 socket using a manufacturer-supplied, non-rewireable moulded plug with partially insulated pins and a fuse rated at no more than 5A.

The system must also include protection that prevents hazardous voltage remaining accessible when the plug is removed. Anti-islanding protection will disconnect the inverter when the mains supply is lost, so the system will not continue energising the circuit during a power cut.

A product having a three-pin plug will not by itself prove that it is compliant. The plug forms part of a complete assessed product, and generic imported inverters or solar kits do not automatically qualify under the new rules.

No extension leads, multi-way adaptors or plug converters

The specification explicitly prohibits connecting plug-in solar through:

• extension leads;
• multi-way adaptors;
• travel adaptors or plug converters; or
• plug-in RCD adaptors.

The device must connect directly to a suitable socket using the approved cable and plug supplied or specified by the manufacturer.

One device per household initially, then one per socket circuit

The interim specification is designed to allow one plug-in solar device per household socket circuit. It even explains how consumers can identify whether two sockets are on the same circuit by switching off individual breakers at the consumer unit.

However, the current version of Engineering Recommendation G98 still restricts Great Britain to one plug-in solar device per household. That existing network rule continues to apply until G98 is amended.

After the amendment, a home could potentially use more than one compliant kit where the sockets are on separate eligible circuits. Two systems on the same circuit will not be permitted, and plug-in solar cannot be connected to lighting circuits or circuits supplying fixed equipment such as a cooker or boiler.

Batteries remain completely outside the launch framework

The specification applies only to plug-in solar without storage. It does not cover:

• standalone plug-in batteries;
• plug-in solar kits with an integrated battery; or
• a compliant solar kit subsequently connected to or operated with battery storage.

Manufacturers must include a prominent warning that the product is not intended to be used with a battery energy storage system. The government says it will continue developing the evidence base for battery-integrated products, but there is no approval route or launch timetable yet.

DNO notification remains mandatory

Households will still need to notify their Distribution Network Operator when a plug-in solar device is connected or removed. Product documentation must explain the current registration process and include a QR code directing users to the relevant guidance.

The kit must also include a durable label to place at or near the consumer unit, showing that plug-in generation is connected to the property.

Will users need an electrician?

Not as a blanket requirement. The interim specification is explicitly written for installation and operation by ordinary consumers, using an existing socket circuit without requiring a separate export circuit.

The government also rejected calls to make professional installation or a mandatory electrical inspection compulsory for every purchase. Self-installation therefore remains central to the scheme.

However, the final rules are more conditional than simply “plug it into any socket”. Users will be advised to obtain professional help where:

• the consumer unit uses older wired fuses or lacks modern residual-current protection;
• the consumer unit is unlabelled, its condition is uncertain or the correct circuit cannot be identified;
• the socket is damaged, degraded or of uncertain suitability;
• the proposed installation requires changes to the home's fixed wiring or circuit protection; or
• the kit has more than 960W of panel capacity and the user wants assurance that the existing installation is suitable.

Manufacturers must also instruct users to test the relevant protective device periodically while the solar system is producing power. If it does not trip immediately when tested, the user should contact a qualified electrician.

Can users mix panels and inverters from different companies?

The specification strongly points towards approved complete kits rather than unrestricted component mixing.

A compliant device comprises at least one solar panel, an inverter, the AC connection lead and UK plug, compatible DC cables and connectors, and an appropriate mounting system. The complete product - not merely the inverter - must meet the specification.

Consumers may still be expected to connect the supplied panels, inverter and cables during installation. But the components and approved configurations must be specified by the manufacturer:

• DC connectors must use matching pairs from the same product family;
• adaptor cables must be assembled or approved by the manufacturer;
• only specified or approved connection cables may be used; and
• components must not be changed or replaced outside the manufacturer's instructions.

In practice, a manufacturer could offer several compliant versions of the same system - perhaps with two, three or four panels - but a consumer should not assume that an unrelated panel, inverter or cable can be substituted while preserving compliance.

Where can plug-in solar kits be installed?

The specification places much more emphasis on mounting and fire safety than many early descriptions of “balcony solar” suggested.

An approved mounting system must be supplied for the intended installation type and supported by structural calculations covering relevant UK wind and snow loads. The manufacturer must state the permitted mounting surfaces, environments and maximum installation height.

Mounting arrangements relying solely on cable ties, rope, string, adhesive tape, bungee cords or straps are prohibited.

Some balconies, cladding and buildings are explicitly excluded

The specification says products must not be installed on:

• timber balconies;
• timber cladding;
• aluminium or metal composite cladding systems;
• high-pressure laminate cladding systems; or
• buildings undergoing external-wall or building-safety remediation.

Panels must not obstruct escape routes or be positioned in a way that increases the risk of fire spreading between homes. They also must not be fixed to walls or building elements that form a property boundary between dwellings.

Renters, leaseholders and residents of managed buildings remain responsible for obtaining any required permission from the landlord, freeholder, managing agent or relevant authority. Planning permission, listed-building consent and insurance implications may also need to be checked.

Is plug-in solar legal in the UK now?

No, not yet through the new consumer plug-in route.

The product specification has now been finalised, but publishing a specification does not itself amend the law. The government still needs to complete and commence changes to the Plugs and Sockets etc. (Safety) Regulations and the Electricity Safety, Quality and Continuity Regulations.

Until those changes take effect, products cannot lawfully be sold and used in the intended plug-in form merely because they appear to meet the new technical specification.

What happens next, and when could products launch?

The government says it intends to lay a Statutory Instrument before Parliament very shortly after publishing the consultation response. Consumer guidance is expected to be available when the regulations come into force.

The remaining milestones are:

• the regulatory amendments are laid and a commencement date is confirmed;
• government consumer guidance is published;
• manufacturers complete the necessary testing and technical documentation;
• products are assessed and identified as compliant on the ENA Type Test Register before being placed on the market;
• retailers begin listing approved complete kits; and
• G98 is amended if the intended move from one device per household to one per circuit is to take effect.

No firm first-sale date has been announced. The publication of the interim specification is nevertheless a major step: manufacturers now have the document needed to finalise compliant UK product combinations while the legal amendments are completed.

What should buyers check when UK products appear?

When retailers begin selling plug-in solar kits, price and panel wattage will not be enough to judge whether a system is suitable or compliant.

• Complete product: the panels, inverter, plug, cables, connectors and mounting option should form a manufacturer-approved configuration.
• Specification declaration: the complete product should be marked as complying with the Plug-in Solar Device Interim Product Specification.
• ENA listing: the device must have been assessed and identified as compliant on the ENA Type Test Register before sale.
• 800VA inverter limit: check the maximum AC output, separately from the total panel wattage.
• Panel capacity: kits can use up to 2,000W of panels, but systems above 960W should advise users to consider an electrical assessment.
• Mounting approval: confirm that the supplied or approved mounting system is suitable for the exact surface, height and location you plan to use.
• Property suitability: check the socket, consumer unit, circuit protection, permissions, planning position and insurance before installation.

Until the regulations commence and approved products can be verified, consumers should avoid buying a generic imported kit on the assumption that it will automatically qualify later.

Key takeaways

• The new interim specification is now published. The main product rules are settled, although the legal amendments are not yet in force.
• Output is capped at 800VA. The inverter cannot supply more than 3.5A to the household circuit.
• Approved kits can include up to 2,000W of panels. Up to four panels are permitted, but customers using more than 960W should be advised to consider an electrical assessment.
• Self-installation remains possible. An electrician is not mandatory for every household, but older or uncertain electrical installations may need professional assessment or upgrading.
• Batteries are excluded. Launch products cannot include or operate with battery storage.
• Products are complete approved systems. Arbitrary mixing of panels, inverters, connectors and cables is not supported by the specification.
• One device per household still applies for now. The specification permits one per eligible circuit, but that depends on a future G98 amendment.
• Not every balcony or wall is suitable. Timber balconies and several cladding types are expressly prohibited.