Three changes, one day

One: the products became lawful

Until 27 August 2026, plug-in solar microgenerators could not lawfully be sold, supplied or used in the UK. Two separate obstacles applied: the ESQCR required compliance with British Standard Requirements written around fixed installations, and BS 1363 does not permit plugs to be used to connect generating equipment. SI 2026/848 removed both for this narrow class of device.

Two: the specification set the limits, and kept batteries out

The Interim Product Specification Version 2.0 sets 800 VA apparent power, up to 253 V, four modules maximum with no more than two in series, and an IP55 socket where the plug sits outdoors. It applies only to plug-in solar devices.

It expressly does not apply to plug-in battery systems, or to plug-in solar devices integrated with battery systems. Consultation respondents argued that this reduced the payback available to consumers, since a plug-in panel generates in the middle of the day when many households use least. The exclusion was retained.

The practical consequence is that a kit advertised with a battery is not covered by the specification that makes plug-in solar lawful here.

Three: the planning rules changed, and excluded timber

On the same day, the permitted development right for solar equipment on a house, a block of flats or a building within the curtilage was updated. For houses and for blocks of flats alike, the new rules list a prohibition on wooden wall, balcony and timber-clad installation, annotated as applying to plug-in solar.

Balcony solar is the name the market gave it. A large share of British balconies are timber or timber clad. Where that is the case, the permitted development right does not cover the installation, and a planning application would cost more than the device.