Solar fires are rare. But a fire on a large commercial roof can be serious, and your insurer will want to know the system was designed and installed properly. Here is what good practice looks like, in plain English.

How common are solar fires?

The main UK study, by the BRE National Solar Centre for government, found around 80 fire incidents, roughly 0.01% of installations. In more than a quarter, the solar system wasn’t the cause.

Where the solar was to blame, the usual causes were:

  • DC isolators, about 30% of incidents,
  • DC connectors, often where plugs and sockets from different makers were mixed,
  • inverters,
  • and, overall, poor installation in about a third of cases.

So most fires come down to a few components and the quality of the work.

RC62: the guidance insurers use

RC62 is a joint code of practice from RISCAuthority and the Fire Protection Association, backed by Solar Energy UK. The current version came out in 2023. Insurers often expect commercial rooftop systems to follow it. Key points:

  • The roof. Mount panels on a non-combustible roof where possible. A new system must not lower the fire performance of the roof.
  • Fire walls. Leave a gap of 2.5 metres of panels either side of a fire or compartment wall, or 1.2 metres where every part of the roof is non-combustible. Don’t run cables over fire walls.
  • Fewer DC isolators. Use as few as the design allows, as they are a common failure point.
  • Connectors done right. Never mix connectors from different manufacturers. Use the right crimp tool and keep connectors off the roof surface.
  • Tidy cabling. Cables on proper supports, never lying in water.
  • Inspections. Check the work in stages during installation, then inspect at least once a year, ideally with thermal imaging.
  • Signs and switches. A “PV on the roof” sign at the main switchboard, and a firefighter DC isolation switch where needed.
  • Talk early. Speak to your insurer and the fire authority before you install, and update your fire risk assessment.

RC62 is being revised, with roofing and solar bodies discussing a more risk-based approach for some flat roof insulation. We’ll update this guide when the new version is out.

What does the latest research say?

A 2025 review for the Building Safety Regulator found fire can spread much faster under panels when the gap between panels and roof is too small. It recommended non-combustible roof coverings under arrays, minimum gaps and breaking large arrays into sections. It isn’t official policy yet, but it points the same way as RC62.

The wiring rules

All solar wiring must meet BS 7671, the UK wiring regulations. Section 712 on solar PV was fully rewritten in 2022. You should get an Electrical Installation Certificate at handover.

What insurers expect

  • Tell your insurer before installation, as RC62 recommends.
  • Expect questions about RC62, inspections and maintenance.
  • Some insurers suggest regular visual self-checks, thermal checks of inverters, isolators and connectors, and keeping combustible items well away from inverters.

Building Regulations

Building Regulations normally apply to roof-mounted solar. The roof’s ability to carry the load must be checked, and the electrical work is covered too. Your installer should handle the Building Control notification.

Questions to ask your installer

  1. Will the design follow RC62?
  2. Is the roof non-combustible? If not, how will you manage the risk?
  3. How will you treat fire walls and separation across the roof?
  4. How many DC isolators will there be, and where?
  5. Will all connectors be the same make, fitted with the right tools?
  6. What inspections happen during and after installation, and is thermal imaging included?
  7. Where will the signs and firefighter isolation go?
  8. Will I get a BS 7671 certificate and Building Control sign-off?

What we do

We design commercial systems with fire safety in mind from the start, and installs are delivered with certified partner installers. See what every installer should include, or get a quote →

Related: How a commercial solar system is designed · Commercial solar payback

Sources

Facts last checked 8 October 2026. This is general guidance, not fire safety or legal advice.