Solar Panels, Fire Risk and Insurance for Business Premises

Are solar panels a fire risk on business premises?

A three-year study by the Building Research Establishment (BRE), published by the government in 2017, reviewed fires involving solar PV systems and concluded that "the incidence of such fires is very low", while recommending better installation practice (GOV.UK).

The UK insurers' code, RC62, puts it the same way: a PV system that is not correctly designed, installed or maintained can add to the fire risk, as any electrical service can. It names three causes that matter to an owner (RC62):

• Installation. The largest single cause. The BRE study found DC connectors, inverters and DC isolators accounted for 84% of PV system related fires
• Product failure. The second largest cause, reduced by checking the products installed are compliant and by proper testing and commissioning
• Neglect over the years. Dirt, moss, lichen and bird droppings can cause hot spots on panels; RC62 says such hot spots have been known to develop into faults leading to fire

None of that is a reason to avoid solar. It is a reason to choose a competent installer, to put the system on a suitable roof and to keep it inspected. Our guide to choosing a commercial solar installer covers how to check who you are dealing with.

What insurers ask for

RC62 tells building owners to discuss the project with the current or prospective property insurer early. The insurer may have requirements of its own, from company policy to what it knows about the building, its contents and the insured value. RC62 also says to settle who owns the system, because the owner of the building and the owner of the panels may not be the same, as under a rooftop PPA (RC62, 5.1.2).

Before you sign a contract, ask your insurer or broker:

• Do you have your own PV requirements?. Some insurers follow RC62 closely, others have their own terms. Get them in writing and give them to the installer
• Does the roof need checking?. Especially insulated sandwich panels or any roof whose fire rating you don't know
• Who insures the system itself?. The building policy, a separate policy, or the PPA provider's cover if you don't own it
• What records do you want?. Commissioning certificates, test results and yearly inspection reports
• Do you need to know about a battery?. Almost certainly yes, and it is covered by a different guide (below)

The joint fire code installers follow

RC62, "Recommendations for fire safety with PV panel installations", is a joint code of practice developed through RISCAuthority (a group of UK insurers) and MCS, published by the Fire Protection Association. Version 2 came out in 2023 and focuses on commercial rooftop systems. RC62 says that using it is voluntary and that it does not replace legal requirements (RC62, FPA). These are the points in it that a business owner will see in a proposal:

A historic or heritage building may need extra fire protection measures, which RC62 says to identify in advance. Our page on planning permission covers listed buildings.

Isolation, inspection and records

Solar panels make DC electricity whenever there is daylight, so switching off the mains does not make the panel side safe. That is why RC62 asks for a fire service switch on commercial systems where it is required: operating it should at least make the DC wiring inside the building voltage-free, and it should be tested during routine maintenance with the results recorded (RC62, 5.14.6).

For the years after installation, RC62 says to inspect at least annually, to clean to a planned programme (insurers expect one for commercial systems), and to maintain the system to the installer's instructions and BS EN IEC 62446-2. It recommends live online monitoring, because error messages give early warning of a fault. Our guide to solar maintenance goes through what that involves.

Keep the handover file. RC62 says the handover documents may form the health and safety file required by the Construction (Design and Management) Regulations 2015 (HSE). Insurers, future buyers of the building and anyone maintaining the system will ask for it.

Batteries and fire

RC62 does not cover battery energy storage. It points to a separate RISCAuthority guide, RE1, for commercial lithium-ion battery installations (RC62, 2.5). If you are adding a battery, ask the installer where it will go, how it will be protected and ventilated, and tell your insurer about it as a separate item. Our guide to commercial battery storage covers when a battery is worth it.

Telling your insurer: a short checklist

• Before the contract. Tell the insurer what is planned: roof, size, any battery, who will own it
• During design. Give the installer the insurer's requirements, and ask how the design meets them
• At handover. Send the insurer the commissioning certificate and test results if they ask
• Every year. Keep the inspection reports and any repair records
• When anything changes. New roof works, a battery, extra panels or a change of owner

A survey is where this starts. The installer looks at the roof, the electrical supply and where cables and inverters can go, so the design can meet your insurer's terms from the start.