The Department for Energy Security and Net Zero (DESNZ) has issued the final interim product specification for plug-in solar devices, dated July 2026 and identifying itself as Version 2.01. The document sets out "technical and safety requirements for plug-in solar photovoltaic devices" intended for connection to an existing low-voltage electrical installation using a standard UK mains plug and socket, without a separate electrical circuit for export1.
The specification applies to single-phase plug-in solar for domestic use, with a rated voltage of up to 253 V (AC), a rated frequency of 50Hz and a maximum apparent power not exceeding 800 VA1. It defines a plug-in solar device as comprising at least one PV module, a grid-following inverter, a connection lead fitted with a plug complying with BS 1363 and a mounting system for the panel, and states that the device is "intended for installation and operation by ordinary persons"1.
Key limits in the document include:
| Requirement | Limit |
|---|---|
| Maximum apparent power to the mains installation | 800 VA1 |
| Maximum current | 3.5 A1 |
| Maximum sum of PV module DC power output | 2000 W1 |
| PV modules per inverter | Up to four1 |
| PV modules in series within any string | No more than two1 |
| Open circuit voltage at inverter inputs | Not exceeding 120 V DC1 |
| Devices per household final ring circuit | One1 |
The specification states that only one plug-in solar product shall be used per household final ring circuit, and notes that current network requirements, Engineering Recommendation G98 Issue 2 Amendment 1 2026, restrict this to one device per household1. It adds that G98 applies to Great Britain only, that Northern Ireland connection requirements are set out separately by Engineering Recommendation G98/NI, and that application of the specification to Northern Ireland is subject to further consideration and may require amendment1. The document also states that consumers installing devices with a total PV module maximum power above 960W "should consider professional assessment"1.
The specification does not apply to other technologies, including PV systems under BS 7671 Section 712, building-integrated PV, plug-in battery systems, plug-in solar PV devices integrated with battery systems, and plug-in electricity generation from sources other than solar PV panels1. Devices are to be classified as Class I or Class II equipment under BS EN 611401.
"A plug-in solar device comprises of at least one PV module, a grid-following inverter, a connection lead fitted with a plug complying with BS 1363 and a mounting system for the panel."
Separately, a distributor guide reports that the government passed legislation on 17 July 2026 making self-installation possible, set to come into force on 27 August, and that plug-in solar panels will be available for UK households to buy and install in August 2026 at the earliest2. It reports that in June 2026 five bodies including the Electrical Contractors' Association made a joint statement saying that without proper safety procedures ahead of the rollout "there is a serious risk of avoidable hazards in homes", while a government-commissioned safety study concluded that plug-in PV is compatible with UK domestic electrical systems2. The same guide reports a standard kit of two panels at 400-450 W each with an 800W microinverter costing around £500, and savings figures of up to £115 per year from EcoFlow and £70-£110 from the government2. These commercial and savings figures do not appear in the specification itself1.
Why it matters for households
The specification is the document that sets the boundaries within which a plug-in solar device can be sold for connection to an ordinary UK socket. For a household, the practical effect is that a compliant device is capped at 800 VA of apparent power and 3.5 A of current, with a maximum of four PV modules and no more than two in series per string1. The 2000 W ceiling on total module DC power is higher than the 800 VA AC limit, so a kit can carry more panel capacity than the inverter will ever export1.
The one-device-per-household restriction comes from network requirements rather than the product rules alone, and the specification notes that this applies unless and until G98 is amended1. Households in Northern Ireland are not covered on the same basis, as connection requirements there are set separately and application of the specification is subject to further consideration1. The document also excludes plug-in battery systems and solar devices integrated with batteries, so a system that stores surplus generation falls outside this framework1.
What happens next
The specification states that it may be modified or superseded to allow for new technical innovations and to reflect future British Standards specific to plug-in solar products1. The distributor guide reports that the legislation enabling self-installation comes into force on 27 August 20262. No date for a final, non-interim specification has been reported1.
Sources2 cited
- Final interim product specification, assets.publishing.service.gov.uk
- Plug-in solar panels: are they worth it? UK, 2026, sunsave.energy