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Commercial Solar Maintenance and Repairs in London
Planned maintenance, inspection, fault-finding and repairs for solar PV on offices, warehouses, industrial units, schools and other commercial buildings, including systems we did not install.
A commercial array can lose a string, an inverter or its monitoring and keep running at part output for months before anyone notices, because nobody is watching the figures. Solar Panels London is an MCS certified installer covering London and roughly 50 miles around it. We look after commercial systems with planned visits and reactive call-outs, and we tell you plainly what the system is doing and what, if anything, it needs.
Why commercial solar needs planned maintenance
Lost output goes unnoticed
On a large roof, one string or one inverter down still leaves the rest generating, so the building keeps running and the loss only shows in the yield. That is money the system was bought to save.
Insurers expect it
RC62, the joint code of practice on fire safety with PV published by the Fire Protection Association with RISCAuthority, MCS and Solar Energy UK, recommends that commercial systems are inspected by a competent person at least once a year, and that a regular cleaning programme is in place. Individual insurers may set their own conditions, so check your policy.
You have a legal duty to maintain it
A rooftop array is part of the building's electrical system. Under the Electricity at Work Regulations 1989, systems must be maintained, as far as is reasonably practicable, so as to prevent danger. Records of inspection and testing are how you show that.
Equipment warranties are a further reason. Manufacturers can ask for evidence that a system has been installed and maintained properly before they accept a claim, and an inverter replaced under warranty on a commercial site is far easier when the fault history and test results are already on file. Our guide to solar and battery warranties explains how they work.
What a planned maintenance visit covers
Every site is different, so the scope is agreed with you before the first visit. A typical planned inspection follows the maintenance approach in BS EN IEC 62446-2 and covers:
Performance against expectation
Generation compared with what the array should produce for its size, orientation and the time of year, using your monitoring data, so that gradual losses show up rather than hiding in seasonal swings.
Modules, mounting and the roof
Cracked or discoloured panels, hot spots, soiling, shading that has appeared since installation, and the condition of rails, clamps, ballast and the roof membrane or covering where the array meets it.
DC and AC electrical testing
String voltage and current checks, insulation resistance testing, and inspection of cabling, connectors, isolators, protective devices and earthing, with results recorded for your file.
Inverters
Fault and event logs, firmware, operating temperatures, ventilation and mounting, on single and three-phase systems. A unit that has been tripping quietly shows up here.
Export limits and grid settings
Where a site has an export limitation scheme or was connected under G99 with conditions, we check the limiting equipment and settings are still configured and working as intended.
Safety, labelling and access
Warning labels, isolation points, fire service information where fitted, and whether the array can be reached and isolated safely by your own maintenance staff and contractors.
You get a written report: what we found, what needs attention now, what can wait, and the test results. If nothing needs doing, the report says so. It is written to be handed straight to an insurer, an auditor or the next contractor.
Commercial solar repairs and fault-finding
If something has already gone wrong, we diagnose before we replace anything. The faults we are most often asked to look at on commercial systems are:
- an inverter showing a fault, tripping, or shutting down on sunny days
- one or more strings producing nothing, so the array runs at part capacity
- insulation or earth faults that trip the system, often worse in wet weather
- monitoring that has gone offline, so nobody can see what the system is doing
- damage after storms, roof works or pigeons nesting under the array
- output that has drifted down with no obvious cause; our guide to solar generating less than it used to covers the usual reasons
Where an inverter is beyond economic repair or no longer supported, we replace it and handle any notification or application to the network operator. Our inverter replacement page covers the options, and our guide to commercial G99 grid connections explains when a change needs approval.
Before an engineer arrives
It helps to know what the monitoring is showing and when the problem started. Please do not let staff open inverters, remove covers or disconnect DC cabling. A solar array is a live DC source whenever there is daylight on it and cannot be switched off at the panels.
Systems installed by someone else
Many commercial arrays outlive the relationship with the company that fitted them. The installer may have closed, been sold, or simply stopped responding, and the building may have changed hands since. We take on maintenance of systems we did not install. If the original documentation is missing, working out what is on the roof and how it is wired is part of the first visit, and you end up with a proper record of the system.
If the roof itself needs work, panels can be taken down, stored and refitted, with the electrical side re-tested and recommissioned afterwards. Our guide to removing solar panels for roof repairs explains how that is planned.
Who we work with
Facilities and property managers, landlords and managing agents, and business owners who want someone accountable for the system on the roof. We work around how your site runs: access, permits, working at height and isolation are planned with you in advance, and visits are timed to suit the building.
We cover warehouses and logistics, offices and commercial buildings, manufacturing, schools, retail, healthcare and leisure facilities. For homes, see our domestic solar servicing page.
Common questions
How often should a commercial solar system be inspected?
At least once a year is the benchmark set by RC62, the insurance industry's code of practice for PV fire safety, and it is what most maintenance contracts are built around. Larger systems, sites with heavy soiling or bird activity, and systems with a history of faults are worth looking at more often, and any system is worth checking after severe weather.
Do you maintain systems you did not install?
Yes. You do not need the original installer's paperwork to book, although it helps if you have it.
Do you offer planned maintenance contracts as well as one-off visits?
Both. Some clients want a single inspection and report, for example before a renewal with their insurer or after buying a building with solar already on the roof. Others want an annual or more frequent programme. The scope and frequency are agreed with you for the site.
Do you clean commercial solar panels?
Yes. We clean with deionised water and a pole-fed brush system, without detergents and without walking on the panels. Cleaning on a commercial roof should be done by people who understand the electrical and fire risks, so it is usually best combined with an inspection visit.
What does commercial solar maintenance cost?
We quote each site individually. The main factors are the size of the system and the number of inverters, roof access and any equipment needed for working at height, how often you want visits, whether cleaning is included, and the condition of the system at the first visit.
Which areas do you cover?
All of London and roughly 50 miles beyond it. If you are not sure whether your site is covered, ask.
Request a commercial solar assessment
Tell us about the site, the system and what is or is not happening, and we will arrange an inspection. If you are not sure what is on the roof, that is a normal starting point.
Monday to Friday, 9am to 5pm. We reply to enquiries within one working day.
Solar Panels London. Last reviewed 9 November 2026. Guidance referenced: RC62 Joint Code of Practice for fire safety with PV panel installations (version 2, 2023), BS EN IEC 62446-2:2020 and the Electricity at Work Regulations 1989. Insurer requirements vary; check your own policy.
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