← Back to blog
30 October 2026

Solar Strings Under Scrutiny: Wiring Faults a Scope 12 Inspection Aims to Catch

A Scope 12 inspection can make the difference between a solar installation that performs safely and one that carries hidden risk. Many PV systems look fine from the outside, yet wiring faults, poor documentation, or installation errors can still create unsafe situations, raise the chance of defects, and complicate insurance claims. That is exactly why solar strings deserve close attention.

At Wassenaar Inspecties, a SCIOS Scope 12 inspection is designed to check whether a PV installation meets building rules, safety requirements, and electrotechnical rules. The inspection combines document review, visual checks, measurements, and thermographic examination to identify common installation mistakes before they lead to bigger problems. In this article, you will learn what solar strings are, which wiring faults matter most, how a Scope 12 inspection approaches them, and what you can do to prepare.

What is a Scope 12 inspection?

A SCIOS Scope 12 inspection is an inspection for solar panel installations. Its purpose is to verify whether the PV installation is safely installed and operates in line with relevant requirements.

During the inspection, Wassenaar Inspecties checks whether the installation complies with:

The inspection also focuses on the technical quality of the system. That matters because improperly installed solar panels can lead to serious safety problems and possible property damage.

What are solar strings in a PV installation?

In a solar installation, a string is a group of solar panels connected together as part of the DC side of the system. Because panels in a string work together electrically, the quality of the wiring, connections, and layout directly affects both performance and safety.

If the string is poorly designed, incorrectly connected, or installed without proper supporting documentation, problems may remain unnoticed until they cause overheating, faults, or unsafe operating conditions. That is why string-related issues deserve careful inspection.

Why wiring faults in solar strings are such a concern

Wiring faults in PV installations are not always obvious. A system may still produce power while hidden defects remain in the background. Over time, those defects can contribute to:

Wassenaar Inspecties highlights that many solar panel systems are not installed in the correct way. Because of that, an inspection is not just a formal step. It is a practical way to reduce risk and confirm that the installation has been built with care.

Which wiring faults does a Scope 12 inspection aim to catch?

A Scope 12 inspection is broader than a quick visual glance at the panels. It looks at the installation as a complete system. When it comes to solar strings, the goal is to identify the kinds of issues that often arise from installation mistakes.

Incorrect or incomplete documentation

One of the first things checked is the drawings and documents. Wassenaar Inspecties reviews them to determine whether the materials meet the installation requirements.

For Scope 12, clients are asked to provide documents such as:

A missing or unclear string plan can make it harder to confirm whether the installed wiring matches the intended design. Good documentation helps reveal whether the installation has been executed correctly.

Wiring that does not meet installation requirements

The inspection checks whether the material complies with the installation requirements. In practice, that means the system is examined not only as a set of panels, but also as an electrical installation where components and connections must fit the intended design and rules.

If materials or installation choices do not align with requirements, the installation may carry higher risk of malfunction or unsafe operation.

Problems visible during inspection

Visual inspection remains a core part of Scope 12. Wassenaar Inspecties carries out visual inspections to detect common installation errors.

This can help uncover issues connected to:

A visual check is especially important because many wiring faults first show up through small but telling inconsistencies in the way the system is arranged.

Irregularities in electrical values

Wassenaar Inspecties also measures the voltage/current of the installation as part of Scope 12. These measurements help build a more complete view of how the solar strings and connected components are functioning.

Electrical measurements are valuable because they can indicate whether a string behaves as expected. If measured values do not align with what the installation should deliver, that can point to underlying issues that deserve correction.

A Scope 12 inspection also includes thermographic examination. Thermography is used to identify abnormal heat patterns that may suggest trouble within the installation.

In electrical systems, unexpected hot spots can be a warning sign. In a PV installation, thermographic checks support the wider inspection by revealing conditions that are not always visible during a standard visual review.

Positioning and installation setup issues

Wassenaar Inspecties checks the position and angle of the solar panels as part of the inspection. While that is not only about wiring, installation layout can influence how the whole PV system is assessed.

An effective Scope 12 approach looks at the broader installation context, not just isolated cables or connectors. That supports a more reliable judgment of safety and compliance.

How Wassenaar Inspecties performs a Scope 12 inspection

Wassenaar Inspecties provides SCIOS Scope 12 inspections for solar panel installations and states that it is officially SCIOS Scope 12 certified. The company also advises clients to rely only on inspection bodies with official SCIOS Scope 12 certification.

The Scope 12 inspection process focuses on a thorough review of the PV installation.

Core inspection elements

Wassenaar Inspecties checks:

All of this is intended to help prevent common installation errors.

Inspection independence

Wassenaar Inspecties works independently and focuses exclusively on inspections. If repair work is needed after an inspection, the customer’s own installer arranges it. That independent position supports a neutral assessment of the installation.

Reporting after the inspection

After every inspection, an official report is prepared by the inspector. In addition, clients receive concrete findings so they can quickly understand whether there is risk of defects or unsafe situations.

If a serious finding is identified, the customer is expected to have the issue resolved by an external company and then send the Herstelverklaring back so an inspector can review whether the repairs were carried out correctly.

Equipment used during Scope 12 inspections

For Scope 12 inspections, Wassenaar Inspecties uses:

All instruments are stated to be properly calibrated on time. Reliable inspection equipment matters because Scope 12 depends on dependable measurements and accurate assessment of the PV installation.

What clients should expect before, during, and after a Scope 12 inspection

A clear process helps the inspection run efficiently and reduces delays.

Before the inspection

Before any inspection takes place, Wassenaar Inspecties sends the client an Inspectierapport. This form must be completed and signed so there is permission to work at the location and in the fuse box.

For a Scope 12 inspection, it is helpful to provide:

During the inspection

During the inspection, the client is advised:

These simple steps support a smooth and thorough inspection.

After the inspection

After the inspection:

  1. The inspector prepares an official report.
  2. Any important findings are shared.
  3. If serious issues are found, the customer arranges repair through an external company.
  4. The customer sends a Herstelverklaring for review of the completed repair work.

Practical tips to reduce Scope 12 issues before inspection

If you want your Scope 12 inspection to proceed smoothly, start with the basics.

1. Organize your documents

Make sure your drawings and supporting documents are available in advance. In particular, gather the:

Good documentation helps the inspector compare the intended installation with what has actually been built.

2. Keep access clear

Ensure the fuse box is accessible and not blocked. Easy access allows the inspector to work efficiently and safely.

3. Avoid informal adjustments

If changes have been made after installation, verify that the documentation still reflects the actual setup. A mismatch between the system on paper and the system on site can complicate the inspection.

4. Act quickly on serious findings

If the inspection identifies a major issue, arrange corrective work promptly through your installer or another external specialist. Then return the Herstelverklaring so the repair can be reviewed.

Why businesses choose Wassenaar Inspecties for Scope 12

Wassenaar Inspecties focuses on inspections of business assets and offers SCIOS Scope 8, Scope 10, and Scope 12 inspections. For businesses with solar installations, that means working with a company that understands how inspection fits into broader operational safety.

The company has had the opportunity to conduct inspections at locations such as the Courthouse of Breda, the municipalities of Breda, Drechstede, Dordrecht, Bergen op Zoom and Steenbergen, as well as The Dutch Bank. It also routinely inspects large chains including New York Pizza, Lidl, Eazie, Basic Fit, Bagels & Beans, Cotti Coffee and Bakker Bart.

Clients can reach Wassenaar Inspecties Monday to Friday, from 09:00-17:00 for questions about services and guidance through the inspection process. The estimated waiting time depends on the size of the installation, and for 1 or 2 fuse boxes the expected waiting time is around 3 weeks.

The company states that all inspectors meet high standards. An MBO 4 Elektrotechniek education is required, along with the relevant Scope 8, 10 or 12 certificate. Inspectors also undergo a thorough audit once every three years.

If your business manages multiple electrical risks, it is often useful to view Scope 12 as part of a wider inspection strategy. Related topics include:

Together, these services help businesses create a safer environment across different types of installations and assets.

Locations and availability

Wassenaar Inspecties can be quickly on-site anywhere in the Netherlands and has the following branch locations:

Branch Address
Breda Schapenweide 1, 4824 AN Breda
Amsterdam Keizersgracht 482, 1017 EG Amsterdam
Bergen op Zoom Zuidzuidehaven 39 A, 4611 HC Bergen op Zoom
Eindhoven Hurksestraat 64, 5652 AL Eindhoven
Leeuwarden Lange Marktstraat 1, 8911 AD Leeuwarden
Den Haag Platinaweg 25, 2544 EZ Den Haag
Enschede Wethouder Beversstraat 185, 7543 BK Enschede
Groningen Leonard Springerlaan 35, 9727 KB Groningen
Rotterdam Corkstraat 46, 3074 AC Rotterdam

Conclusion

A Scope 12 inspection is built to do more than tick a box. It checks whether a solar installation meets building rules, safety requirements, and electrotechnical rules, while also reviewing the areas where solar string and wiring faults often hide: documents, visible installation quality, electrical measurements, thermography, and installation setup.

For businesses that want confidence in the safety and technical quality of their PV installation, a structured and independent inspection is a practical step. If you want to schedule a SCIOS Scope 12 inspection, request a quotation and get in touch with Wassenaar Inspecties for guidance on the process, required documents, and expected next steps.