Updated statement: IET warns Government's plug-in solar plans still leave consumers exposed to electrical safety risks

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

“Our concern has always been broader than the product itself. It has 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 controlled test 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.

"The Government's consultation recognises many of the foreseeable risks, including older wiring, multiple devices connected to the same circuit, the use of extension leads and non-compliant products, as well as consumer misunderstanding. While the strengthened specification is welcomed, many of the proposed mitigations continue to rely on guidance, warnings, product labelling and retailer communications. Safety simply cannot depend on the layperson. Rather than consumers consistently making technically complex decisions, wherever possible, protections should be built into the product by design, standards and installation requirements.

"The proposals place a significant burden on consumers to make judgements that would, traditionally, be expected of a competent electrician. Consumers are expected to identify household circuits, understand the suitability of existing protective devices, such as RCDs, 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 householder and are likely to be even more challenging for those living in older properties or rented accommodation. 

"This is particularly relevant given the age and diversity of the UK's housing stock. Many homes have older electrical installations and householders may be unaware of the condition of their wiring or whether their existing installation provides the necessary level of protection.

“The Government has already recognised these hidden dangers and brought in legislation for the private and social rented sectors where inspections of electrical installations are mandated every 5 years. Not all installations are the same and, until one is inspected, it is not immediately apparent what lies behind the walls. It is therefore absolutely necessary, prior to purchasing a plug-in solar PV unit, to have your installation checked for its suitability. 

"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. This represents a departure from the approach adopted in Germany, where installations are limited to a single plug-in solar PV unit per household. Critically, the safety testing commissioned by DESNZ assessed individual units only and did not examine how multiple units would behave together during normal conditions, fault conditions or during a loss of mains supply.

"The Government is proposing to allow multiple plug-in solar PV units within a single property despite this operating scenario having not been assessed during the testing strategy it commissioned. As a result, important questions remain unanswered about how multiple units would behave in fault or emergency conditions. For example, do multiple plug-in solar PV units affect the RCD’s functionality? Does the RCD shut down quickly enough in the required time to prevent electrocution? Without such testing, it is unclear whether all units would cease generating quickly enough following operation of protective devices or disconnection of the mains supply. This creates uncertainty around whether parts of an electrical installation could remain energised for longer than expected, increasing risk to those using, maintaining or responding to faults on the installation.

"Until there is sufficient evidence that plug-in solar PV can be safely connected across the full range of UK domestic electrical installations without prior assessment, the IET continues to advocate that consumers must have their installation assessed by a competent electrician before connection." 

Plug-in solar PV has the potential to play an important role in expanding access to clean, home-grown energy and reducing energy costs for consumers. However, public confidence in the technology will depend not only on the safety of the products themselves, but also with confidence that they can be safely integrated into the existing electrical infrastructure found in millions of UK homes. Addressing the remaining evidence gaps through further testing, robust product standards, effective market surveillance, clear consumer information and competent assessment of existing installations will be critical to ensuring a safe and successful rollout.