Fire safety and cladding: where you may not install plug-in solar

Why this section of the specification is stricter than the rest

Because people said so during the consultation, and the government agreed.

Respondents raised the risk of fire spreading across the external surfaces of buildings, “particularly when installed on high-rise residential buildings”. The government’s answer was to tighten the document:

In response to these comments, the IPS has been strengthened and adopts a precautionary approach. This includes additional restrictions on the surfaces and locations where plug-in solar devices may be installed on higher-risk buildings and the introduction of minimum fire performance requirements for backing material in PV modules.

It also said it “will continue to keep the fire safety requirements under review in light of emerging evidence” — so this is the part of the framework most likely to change, and the part where a page written a year ago is most likely to be wrong.

Where installation is not permitted

The specification is unambiguous. “Installations shall not be permitted on”:

• aluminium composite material (ACM) or metal composite material (MCM) cladding systems
• high pressure laminate (HPL) cladding systems
• timber cladding systems
• timber balconies
• buildings that are subject to external wall remediation works, building safety remediation works or equivalent restrictions relating to external wall fire safety

Two of those catch people out. A timber balcony is prohibited as a location regardless of how the device is mounted on it — this is not about drilling into the balustrade. And a building under remediation is prohibited for the duration of that work, which means the answer can be no today and yes later.

The requirement on the panel itself

This is the part a retailer is least likely to volunteer, and it is worth quoting in full because it is specific and testable:

The outer most substantial layer of the PV module shall achieve a minimum reaction-to-fire performance equivalent to Euroclass B-s3, d2 in accordance with BS EN 13501-1, when installed on building materials allowed in the product guidance.

Two definitions make that usable. A substantial layer is one that “constitutes a significant part of a PV module” — the specification fixes the threshold at a mass per unit area of at least 1.0 kg/m² or a thickness of at least 1.0 mm. And it notes that in most cases this layer is “what is normally called the ‘backsheet’”.

The specification also requires that the test procedures used to demonstrate that performance “should be specified in the product documentation”. So the question to put to a seller is not “is it fire safe” but: which test demonstrates Euroclass B-s3, d2 for the backsheet, and where is it recorded?

Alongside that:

• the methods of attachment used for the modules “shall be resilient in the event of fire”
• fire safety must be considered at system level — the module, the mounting system and the surface it is installed on, not the panel alone
• the inverter must be designed to minimise fire risk under normal and fault conditions in accordance with BS EN IEC 62109-1, Clause 9

What the specification makes your responsibility

Distinct from the prohibitions, these are framed as things the manufacturer must tell you that you are responsible for:

• ensuring the modules are installed in a way that does not increase the risk of fire spreading along external walls or balconies to neighbouring properties
• ensuring modules are not installed on or fixed to walls or other parts of the building that form a property boundary between dwellings
• keeping escape and rescue paths clear
• observing the required separation distance where the building has a lightning protection system, in accordance with BS EN IEC 52305-3:2024

And two that are about heat rather than fire spread, but belong in the same thought: the manufacturer must specify minimum clearance between the module and the mounting surface, and minimum spacing from adjacent materials, to ensure ventilation and “minimise heat accumulation and minimise fire risk”.

If you are installing on a balcony shared with neighbours above and below, the first two items are not paperwork. They are the reason the restriction exists.

What “higher-risk building” does and does not mean here

The government response describes “additional restrictions on the surfaces and locations where plug-in solar devices may be installed on higher-risk buildings”. “Higher-risk building” is a defined term in building safety legislation, usually tied to height.

But the prohibitions we found in the specification are defined by material — ACM, MCM, HPL, timber — and by remediation status, not by the height of the building. We searched the specification for a height threshold and did not find one.

So we are not going to tell you that plug-in solar is banned above a particular number of storeys, or permitted below one. If your building has none of the prohibited materials and is not under remediation, the specification’s stated restrictions do not turn on its height. If you have found a height threshold we have missed, please tell us.

What we could not confirm

Whether the fire safety requirements have already changed. The government said explicitly that it would keep them under review, and pointed to “final tests” still to be completed in a related passage on protective devices. This page reflects version 2 of the specification as published in July 2026.

Whether retailers will publish the Euroclass evidence. The specification requires the test procedures to be in the product documentation. Whether that shows up on a product page, in a manual, or only on request is something we will only learn once kits are actually on sale here.