IET statement: Government’s response to ‘Plug-in solar: Regulatory amendment and interim product specification’ consultation

Mark Coles, Head of Technical Regulations at the IET, said:

“Our concern has always been broader than the product itself. It’s been about whether the overall regulatory, technical and product safety framework is sufficiently robust for mass-market deployment across the UK's diverse housing stock. A compliant plug-in solar PV unit may perform safely under the conditions for which it has been designed and tested, but regulators must also consider how products are likely to be used in millions of homes, not simply how they are intended to be used.”

“The Government's consultation recognises many of the foreseeable risks, including older wiring, multiple devices connected to the same circuit, extension leads, non-compliant products and consumer misunderstanding. While the strengthened specification is welcome, many of the proposed mitigations continue to rely on guidance, warnings, product labelling and retailer communications, rather than measures that reduce reliance on consumers making technically complex decisions correctly every time.” 

“The proposals place considerable responsibility on consumers to identify household circuits, understand the suitability of existing protective devices, recognise when their installation may require professional assessment, and know when to seek advice from an electrician. These are not straightforward judgements for the average homeowner and are likely to be even more challenging for those living in older properties or rented accommodation.”

There is also a significant evidence gap around the government's proposal to permit multiple plug-in solar PV systems within the same property when connected to different circuits. For example, the proposals would allow consumers to install one plug-in solar unit per circuit, whereas Germany limits installations to a single plug-in solar system per household. The safety testing commissioned by DESNZ assessed individual systems only and did not examine how multiple units would behave together during an electrical fault. Without that testing, it is unclear whether all systems would cease generating quickly enough following operation of protective devices or disconnection of the mains supply. This raises concerns that parts of an installation could remain energised for longer than expected, creating additional risks for users of the electrical installation.

For these reasons, the IET continues to believe that public safety should remain the first principle. Plug-in solar PV has the potential to play an important role in expanding access to clean, home-grown energy at the lowest possible cost but that potential will be best realised where robust product standards, effective market surveillance, clear consumer information and competent assessment of existing electrical installations work together. This is the surest way to protect householders, maintain confidence in the technology and support a safe and successful rollout.