Danger signs that your roof could go up in flames like these did: Solar panel fires up 60% and expected to soar

Jon Stretton has seen more than his fair share of fires caused by solar panels.

But when he was called in to repair faulty panels on a farm in West Berkshire in March, the energy management expert was appalled by what he saw.

Jon, technical director at energy management company OffGrid Pro, said the farmer asked him to evaluate the farm’s 500 solar panels, which were installed on the roof of his cattle shed because they stopped working for a few days every time it rained.

But while inspecting the panels, Jon discovered that a cheap connector used to connect the panels together meant that one of the ‘box joints’, a protective box fitted to the back of the solar panel, had recently caught fire.

Fortunately the fire was out before it spread, Jon says, leaving the box junction blackened and charred.

He says he doesn’t know why the fire went out but warned that hundreds of animals were at huge risk of burning alive in the cattle shed had the fire spread.

He adds: ‘Thank God there was no major fire; But that was just good luck because it could spread easily.

‘We only got the call because the solar panel system was working.’

Solar panels are behind more than 170 house fires a year; Fire crews are now called on average every two days to fight solar panel fires.

Last week, a row of solar panels on a £600,000 new-build house in Wellingborough, Northamptonshire exploded while a family was inside.

Doorbell footage from a house across the street captures the terrifying blaze and shows the roof of the property engulfed in flames on Holiday Monday.

Official data shows that the number of fires related to solar panels has increased by 60 percent in two years.

As Ed Miliband’s ‘solar roadmap’ forces homes and businesses to quickly install new panels, there are also fears the number of fires could rise.

An area more than three times the size of Birmingham will be filled with solar panels within the next five years, according to the Labor Government’s plan.

But the number of fires has increased faster than the number of installations in recent years, according to insurer QBE Insurance, which obtained the data from a Freedom of Information request.

The report found that 171 fires related to solar panels occurred in 2024; this number was 128 in 2023 and 107 in 2022; There was a 60 percent increase in just two years.

According to QBE data, there were an estimated 1.7 million solar panels across Britain in 2024; this number is only up 31 percent from 1.3 million in 2022.

QBE’s Adrian Simmonds says: ‘Solar technology is an important part of the transition to clean energy, but its rapid pace of deployment is a cause for concern.

‘Our analysis shows that fires involving solar panels are increasing at twice the rate of new installations in the two years to 2024.’

Mr Stretton says most fires are caused by poor connections between panels and electrical systems (known as MC4s), substandard parts fitted to panels and dangerous installations.

He says: ‘Unfortunately, we are seeing increasing problems with residential and commercial solar installations.

‘Lives are already being put at risk, but it’s only a matter of time before something worse happens.’

Southampton-based Jon says the risk can be eliminated for as little as £12 and can be as simple as buying an ArcBox that fits the dodgy ports.

Result: The roof became unusable due to fire. According to QBE data, there were an estimated 1.7 million solar panels across Britain in 2024; that number is up just 29.6% from 1.3 million in 2022.

In the case of the farm, he says: ‘When we went up to the rafters for a closer look, we discovered that several of the joints appeared to be crimped rather than approved MC4 joints. ‘Such a weak connection is extremely dangerous.’

Lee Masson, a forensic investigator at Halliwell Forensics, a company called in by insurance companies to help discover the source of house fires, says: ‘There are a wide variety of reasons why a solar system installed on a property could have started a fire.

‘Problems we have encountered include incompatible connectors. If these connectors come from different manufacturers [to the panels] With varying tolerances, there is a chance they will eventually overheat and cause a fire.

‘Bad weather or birds on the roof can loosen or dislodge connections and cause cables to fail; Copper rust on copper creates a green oxidation.

‘This instability is a potential source of fire. There have also been cases of overheating of the electrical inverter or isolation switches, which have failed over time due to loose wiring or incompatible or poorly manufactured products.’

Experts are now encouraging households to have their own plumbing checked urgently.

Mr Masson says cheap Chinese copies of original Swiss MC4 connectors may not be manufactured to the same high standard.

UK fire and rescue services were called to 38,144 building fires in the year ending December 2024. During this period, only 171 calls were related to solar panels.

But Mr. Masson says these fires are among the most difficult types for firefighters to put out.

He adds: ‘The problem you may have with solar panels is that they are on the roof and even if the mains power is switched off the panels are still producing electricity; This is still held like a battery.

‘Emergency services may be cautious about how they deal with this issue as water may not be the ideal solution. ‘Being close to the roof area means a solar fire can easily take hold and spread to other homes.’

He says regular maintenance can significantly reduce the risk of fire. He points out that rental properties must have an Electrical Installation Condition Report every five years. A professional solar panel inspection costs around £200.

Critical component: Chinese copies of original Swiss connectors used to connect panels are suspected to be behind some fires

Mr Simmonds says: ‘Safe installation and maintenance is essential to reduce fires. We strongly recommend that owners contact certified installers and carry out regular inspections.’

While solar connections are the cause of house fires, there are also concerns about lithium-ion batteries now frequently used in solar installations.

These batteries allow households to store electricity for use at night rather than using it as it is produced.

Damage to lithium-ion batteries can cause chemical reactions in units that overheat, for example in high temperatures in summer. It warns that fires may be triggered if flammable gases are released from these batteries.

It says: ‘Battery storage poses additional fire risks when units are installed in lofts, airing cupboards or upstairs areas that are difficult to access in an emergency.

‘Not only do these increase the likelihood of a house fire, they also increase the potential severity of the fire.’

toby.walne@dailymail.co.uk