When Thailand’s Consumer Protection Board (สคบ.) opened a formal investigation into faulty solar installation work in mid-2026, the damage tally was already over ฿40 million across more than 156 complaints filed since 2024. Equipment that melted or burned, solar installations that never produced the promised output, inverters wired incorrectly — and in many cases, customers with no paperwork at all from the installer who sold them the system.

For professional solar installers, this timing matters. The government is tightening quality checks on the residential and small commercial rooftop market, pushing inspections and complaint channels harder than before. A reputable installer with proper records is in a very different position than one who hands over a WhatsApp photo of the finished array and moves on.

This post is a practical documentation checklist — what to capture, when, and why it protects both you and your customer.

What Is Thailand’s Solar Installation Quality Problem?

The surge in complaints follows the rapid growth of the Thai rooftop solar market. As electricity tariffs rose and government incentives brought in new buyers, the number of installers — experienced and inexperienced — grew fast. Faults filed with สคบ. include substandard panels in place of those quoted, inverters that failed within months, roof penetrations that caused water leaks, and DC wiring that posed fire risks. Affected cases span Khon Kaen, Saraburi, and Bangkok’s Thonburi district. Of the 156+ complaints, 84 had been resolved as of mid-2026.

The consumers with the hardest cases shared one characteristic: they had almost nothing in writing from their installer. The crackdown does not target well-documented, quality-controlled work — it targets the gap between what was quoted, what was installed, and whether anyone can prove the difference.

What Kinds of Faults Are Driving the Complaints?

The complaints cluster around three failure types, all rooted in documentation gaps:

Equipment substitution. Panels or inverters of a different brand or lower spec than those quoted, installed without telling the customer. Without a work order recording serial numbers, there is no way to verify what was actually put on the roof.
Wiring and safety defects. DC cable routing that doesn’t follow the system design, earthing omitted, or junction boxes left exposed. These faults appear months later — unless the photos captured the wiring before panels covered the runs.
Performance shortfalls. A 5kWp system producing 30% less than estimated, with no commissioning log to diagnose whether it’s a sizing error, new shading, or a partially wired string.

Each is easier to defend against — or pin down — if the job record is complete.

What Does a Properly Documented Solar Job Look Like?

A properly documented solar installation has six components. They take less than 30 additional minutes spread across a full-day installation job, but they change your legal and commercial position entirely if a complaint comes in.

1. Pre-installation site assessment record. A written note of the roof type, roof condition, shading obstructions noted, and the agreed system design — panel count, inverter model, string configuration, mounting method. If the site has a weak roof slab or an existing leak, that needs to be on record before the first panel goes up.

2. Equipment delivery receipt. Panel brand, model, and serial numbers; inverter brand, model, and serial number. Match these against the quotation. If a substitute is used because the quoted item is out of stock, get written customer approval before installation, not after.

3. Before and during photos. Roof condition before any penetrations. DC wiring runs visible and in conduit before panels cover them. Mounting rail installation, earthing connections, and junction boxes before covers go on. These are the photos that are unavailable if you try to take them the following week.

4. Inverter commissioning record. Date and time of first grid connection, the voltage and frequency readings, string open-circuit voltages, and the inverter’s reported output in the first hour. This establishes the baseline the system was performing to at handover.

5. Handover sign-off. The customer’s name, the installation address, the installed equipment (with serial numbers matching the delivery receipt), the date of commissioning, and the customer’s signature confirming they received a walkthrough of the monitoring app and the system isolator. One page.

6. Post-handover monitoring reference. Note the monitoring portal or app the customer can use to check daily generation, and the contact number for warranty claims. If you installed a system in Bang Kapi that should produce an average of 22 kWh per day in October, the customer knowing how to check that is part of the handover.

Why Before-Site and In-Progress Photos Are Not Optional

Of the six components above, the in-progress photos are the hardest to go back and replicate — and the most important when a dispute arises. A photo of the finished array from the street tells you almost nothing about how it was wired. A photo of DC cabling inside the conduit run, taken before the panels were laid, tells you exactly what was done.

Build a required photo checklist into every solar installation job:

Roof condition before penetrations (one wide shot, one close shot of each penetration zone)
DC cable runs before conduit covers or panel coverage
Earthing conductor at both the mounting frame and the inverter
Inverter wiring before the cover is closed
Completed array from above and from ground level
Inverter screen showing first-day commissioning output

If your technicians complete jobs on a work order that includes a required photo checklist, these images are filed automatically against the job record and the customer account — not sitting on a personal phone that gets replaced in two years.

What Your Work Order Must Capture for Each Job

A solar installation work order is not the same as a residential service job work order. It needs additional fields:

Panel brand, model, quantity, and serial number range
Inverter brand, model, and serial number
String configuration (how many panels per string, how many strings)
Mounting method (rail type, fixing method, roof type)
DC isolator location and type
Earthing method and conductor size
Commissioning date and first-day output

This level of detail sounds like a lot until the customer calls two years later saying production dropped after a storm and wants to know if the wiring was done correctly. With these records, you can answer that question in five minutes. Without them, you are starting from zero.

How Service Records Help When Warranty Claims Come In

Solar panel warranties run 10–25 years; inverter warranties 5–10 years. Manufacturer warranty claims require proof the system was installed correctly and commissioned properly. An installer without a commissioning log or wiring photos can end up caught between a rejected warranty claim and a customer who holds them responsible.

Service history matters for ongoing maintenance too — annual inverter checks, cleaning, resealing roof penetrations. A documented service record strengthens both parties’ position if a performance dispute arises later.

Concrete example: A 6kWp system on a shophouse roof in Nonthaburi underperforms in year three. With a commissioning log, the installer can compare current output against the handover baseline to determine whether it’s panel degradation (covered), new shading (not covered), or a wiring fault (potentially covered). Without that log, the conversation starts from zero — and customer expectations are impossible to manage fairly.

FAQ

What records do Thai solar installers need to keep, and for how long?

There is no single regulation specifying a retention period for installer records, but civil claims in Thailand can be brought up to ten years after a defect is discovered. Keeping the core records — equipment serial numbers, commissioning log, photos, and customer sign-off — for the length of the product warranty is the practical minimum. Cloud-based job records are easier to search and retain than paper files.

What if the customer claims the system is underperforming but won’t let me inspect it?

Your commission log and handover sign-off set the baseline you are responsible for. If the customer can show the monitoring portal output is below that baseline and won’t permit a site visit to diagnose, the dispute escalates — but at least you have a documented starting point. Without commissioning records, you have no baseline to defend.

Does OnSiteQ support solar installation job documentation?

OnSiteQ’s work order flow is designed to capture per-job equipment details, required photos, and customer signatures, with all records filed to the customer account. The platform is currently in early access — and solar installation documentation is one of the core use cases it was built around.

Thailand’s quality crackdown is a signal, not a ceiling. Professional installers who already work to a documented standard have nothing to fear from tighter enforcement — and a real competitive advantage to show customers who have heard the horror stories. Start with a photo checklist and a commissioning log on every job. The records cost you thirty minutes; the protection they provide lasts the life of the system.

Solar Installation Records Every Thai Installer Must Keep