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7 November 2026

Four Documents Before We Arrive: Legplan, Stringplan, Ballastplan & Constructieberekening for Scope 12

If you are preparing for a Scope 12 inspection, one of the easiest ways to prevent delays is to have the right documents ready before the inspector arrives. For many PV installation owners, the biggest frustration is not the inspection itself, but discovering too late that essential drawings or calculations are missing.

For a Scope 12 inspection, Wassenaar Inspecties asks clients to complete and sign the "Inspectierapport" before the visit. In addition, if available, clients are asked to provide four important documents: a legplan, stringplan, ballastplan, and constructieberekening. These documents help the inspection run more efficiently and support a clear assessment of whether the solar panel installation can operate safely and in line with the relevant standards.

In this article, you will learn what each document is, why it matters, and how to prepare for a smoother Scope 12 inspection.

What is required before a Scope 12 inspection?

Before any inspection starts, the client receives an "Inspectierapport" form from Wassenaar Inspecties. This form must be completed and signed so the inspectors have permission to work at the location and in the fuse box.

For SCIOS Scope 12, Wassenaar Inspecties also asks, if possible, for the following documents:

These documents give the inspector a clearer picture of how the installation has been designed and built. That matters because a Scope 12 inspection is focused on checking solar panel installations for safe operation and compliance with relevant standards.

Why these four documents matter for Scope 12

A solar installation is not just a collection of panels on a roof. It is a complete system with electrical, structural, and layout-related considerations. Good documentation helps connect the design on paper to the system in the field.

During a Scope 12 inspection, Wassenaar Inspecties inspects solar panel installations and uses a process that includes:

The visual inspection includes checking whether required drawings are present and whether they contain correct information. That is why these documents are more than administrative paperwork. They support the inspection itself.

The legplan: understanding the physical layout

A legplan shows how the solar panels are positioned on the roof or installation surface. In practical terms, it helps identify where the panels are located and how the array is arranged.

Why the legplan is useful

For a Scope 12 inspection, the legplan helps the inspector:

When panels, sections, or installation zones are clearly mapped, the inspection becomes more structured. This can reduce confusion on site and make it easier to assess visible conditions and possible safety concerns.

Practical tip

Before the appointment, check whether your legplan reflects the installation as it exists today. If changes were made after the original installation, an outdated drawing may slow down the process.

The stringplan: understanding the electrical grouping

A stringplan shows how the solar panels are electrically grouped into strings and connected within the PV system. This is especially important because Scope 12 goes beyond a simple visual review.

Wassenaar Inspecties performs measurements and tests during the inspection, including checks on protective conductors and their connections, circuit impedance of the system, earth resistance of the earth electrode, insulation resistance of each part of the installation, safe separation of circuits, and the correct operation of residual current devices and overcurrent protection.

Why the stringplan matters

The stringplan helps the inspector:

A clear stringplan can also help when components need to be identified quickly during the site visit. In complex installations, that clarity becomes even more valuable.

Practical tip

Make sure the stringplan is readable and current. If naming conventions are used for strings or system sections, keep them consistent with labels used on site.

The ballastplan: understanding load distribution

A ballastplan is relevant where ballast is part of the mounting solution. In general terms, ballast planning helps show how the installation is secured and how weight is distributed.

Why the ballastplan supports a Scope 12 inspection

A Scope 12 inspection is about verifying the safe operation of the installation. A ballastplan contributes context about the mounting approach and system setup, especially where roof-based installations depend on weighted support systems.

For the inspector, this document can help with:

Because installation safety is not only electrical, supporting documentation around the physical setup can play an important role in the inspection workflow.

Practical tip

If your system uses ballast, keep the ballastplan together with the other project drawings so it can be shared before the visit rather than searched for on the day itself.

The constructieberekening: understanding the structural basis

The constructieberekening is the structural calculation report. This document provides the structural basis behind the installation design.

Why the constructieberekening is important

In a rooftop solar project, structural considerations matter because the installation must not only function electrically but also be supported appropriately by the structure beneath it.

For a Scope 12 inspection, the constructieberekening helps by:

This document is particularly helpful when the installation includes roof loading considerations, mounting structures, or project-specific design decisions.

Practical tip

If you have multiple versions of the structural calculation, send the final approved version that matches the installation on site.

What happens during the Scope 12 inspection?

Wassenaar Inspecties provides SCIOS Scope 12 inspections for solar panel installations. During the inspection, the process includes several parts.

1. Visual inspection

The inspector checks:

2. Measurements and tests

The inspection includes measurements and tests of:

3. Thermographic examination

Thermography is used to detect:

This helps identify issues early and supports fire prevention.

4. Official inspection report

After the inspection, an official report is prepared. If deficiencies are found, Wassenaar Inspecties issues a detailed report with recommendations. After corrective actions, a re-inspection can follow.

How to prepare for a smooth inspection visit

Good preparation can save time and help avoid unnecessary follow-up work. Here is a practical checklist.

Scope 12 preparation checklist

  1. Complete and sign the "Inspectierapport".
  2. Gather the legplan.
  3. Gather the stringplan.
  4. Gather the ballastplan.
  5. Gather the constructieberekening.
  6. Make sure the fuse box is accessible.
  7. Avoid interfering with the inspector during the visit.
  8. Keep any installation drawings and supporting documents organized and easy to review.

What if serious defects are found?

Wassenaar Inspecties works independently and focuses exclusively on inspections. If repair work is needed after the inspection, the customer’s own installer or another external company handles those corrections.

If there is a serious finding, the expected next step is clear:

This independent way of working helps keep the inspection role separate from repair work.

Why organized documentation can reduce re-inspection risk

A re-inspection may be necessary after corrective measures. While not every follow-up can be avoided, better preparation gives the inspection a stronger starting point.

When the legplan, stringplan, ballastplan, and constructieberekening are available in advance, the inspector can review the installation with clearer context. That can support a more efficient visit and reduce the chance of avoidable uncertainty around the design or setup.

Quick answers about Scope 12 documents

Which documents does Wassenaar Inspecties request before a Scope 12 inspection?

Before a Scope 12 inspection, Wassenaar Inspecties requests a signed "Inspectierapport" and, if available, a legplan, stringplan, ballastplan, and constructieberekening.

Is the Inspectierapport required?

Yes. Before any on-site visit, the client must fill in and sign the "Inspectierapport" to give permission to work at the location and in the fuse box.

Do I need to keep the fuse box accessible?

Yes. During the inspection, the fuse box should not be blocked from access.

Can Wassenaar Inspecties also do the repairs?

No. Wassenaar Inspecties works independently and focuses only on inspections. Repairs are arranged by the customer through their own installer or another external company.

If you are reviewing your wider inspection responsibilities, it may also be useful to look at:

For organizations managing multiple technical assets, understanding the distinction between Scope 8, Scope 10, and Scope 12 can help plan inspections more effectively.

Practical takeaways

If you want your Scope 12 inspection to run smoothly, focus on preparation first.

Remember these key points:

Conclusion

A successful Scope 12 inspection starts well before the site visit. By preparing the legplan, stringplan, ballastplan, and constructieberekening in advance, you give the inspector a better foundation to assess your PV installation efficiently and clearly.

That preparation supports a smoother process, clearer reporting, and a more effective inspection from the moment the visit begins.

If you are planning a Scope 12 inspection and want guidance on the process, contact Wassenaar Inspecties. The team is available Monday to Friday, 09:00-17:00, and is ready to help answer questions and guide you through the inspection process.