What this guide covers
You can prepare much of the information without climbing onto the roof or opening electrical connections. Collect your electricity use, known roof details and plans for the home, then have the technical assessment and installation developed around them.
Record the roof type, approximate age, known leaks and any available drawings. Take photographs from ground level or a safe existing viewpoint. Do not climb onto the roof to complete a quotation request. Do not assemble or disconnect solar connectors from a generic online drawing. Operating a user control according to its instructions is different from establishing that every part is safe to work on. Does switching off the inverter make maintenance safe? Have the permitted user operations explained. Do not assume all parts become dead when one control is switched off. What should I do about loose panels, crackling or smoke? Keep clear and stay off the roof. Arrange an assessment of damage. Call 112 for smoke, fire or immediate danger.
Copy or print your summary
You can prepare much of the information without climbing onto the roof or opening electrical connections. Collect your electricity use, known roof details and plans for the home, then have the technical assessment and installation developed around them.
Define what you want the system to support
Are you mainly generating for current consumption, or planning an electric car, heat pump or induction hob? Record your annual use and, where available, when that electricity is used.
An annual total does not show how closely consumption coincides with generation. Ask for the assumptions behind an output or savings estimate. A fixed savings figure is difficult to assess without its tariff, export, shading and usage assumptions.
Distinguish Wp, the stated peak panel power under test conditions, from kWh, a quantity of electrical energy. Adding the Wp figures in a quotation does not predict the annual energy your roof will produce.
Collect roof information safely
Record the roof type, approximate age, known leaks and any available drawings. Take photographs from ground level or a safe existing viewpoint. Do not climb onto the roof to complete a quotation request.
Ask for the proposal to cover:
- structural capacity and roof condition;
- mounting suitable for the roof and wind exposure;
- shading, access and future roof work;
- roof penetrations and cable routes;
- inverter position and ventilation;
- the connection to the electrical installation.
Brandweer Nederland provides purchasing and installation advice covering these subjects. Brandweer: solar panels.
A plug does not make every socket suitable
A balcony system can look straightforward because of its plug. NEN explains that PV needs its own final circuit rather than an arbitrary shared household socket. The fire service also recommends assessing the existing installation and avoiding extension leads and power strips. NEN: plug-in solar panels, Brandweer: plug-in solar checklist.
Ask how the proposed system will connect before buying it. A fitted plug does not replace checks of the circuit, mounting or equipment.
Do not assemble or disconnect solar connectors from a generic online drawing. Operating a user control according to its instructions is different from establishing that every part is safe to work on.
Ask for a complete system list
The proposal should specify quantities and models for the selected design.
| Component | What to ask |
|---|---|
| Panels | Exact make, model, quantity and documentation. |
| Mounting system | Roof compatibility, fixings and any required ballast calculation. |
| Inverter or microinverters | Model, quantity, position and maintenance access. |
| Cables and connectors | Compatible system, route and installation responsibility. |
| Electrical protection | Which alterations are required, and why? |
| Monitoring | What can you see, and who controls account access? |
| Handover documents | Drawings, settings, instructions and verification records. |
Eight panels do not automatically need eight identical cables or a standard single inverter. Quantities depend on the system arrangement. Ask for omitted components to be specified before accepting the quotation.
For your preparation, electricity statements, a room or roof sketch and existing property records are enough. Solar-connector crimping tools are not part of these preparation steps.
Compare quotations on equal terms
A proposal that includes consumer-unit work and commissioning checks cannot be compared directly with a materials-only price. List the included activities alongside one another.
Ask who assesses the roof, who handles any remedial building work and how unexpected conditions will be addressed. Agree the applicable product warranties and installation terms, the contact for problems and the maintenance requirements. Conditions from a different brand or an earlier quotation do not automatically carry over.
Keep copies of the final specification and handover documents with your property records. They will help with future roof work, a battery proposal or changes to the electrical installation.
Frequently asked questions
Can I mount the panels and ask someone to connect them later? Agree any work you intend to do yourself in advance. Mounting, roof loading and electrical system choices affect one another. A later connection is not automatic approval of earlier work.
Does switching off the inverter make maintenance safe? Have the permitted user operations explained. Do not assume all parts become dead when one control is switched off.
What should I do about loose panels, crackling or smoke? Keep clear and stay off the roof. Arrange an assessment of damage. Call 112 for smoke, fire or immediate danger.
Prepare your solar project with CAS
Tell CAS Elektrotechniek about the property, electricity use and planned changes. Ask which work and checks your installation needs. Contact CAS about solar panels.
Sources
Materials and specifications
Before buying, check that the size, type and specification suit your installation. Use the article list and tools to work out the quantities you need.
Tape measure and plan
- Quantity and unit
- One tape measure and current plan
- Specification
- Survey accessible surfaces only; measurements do not establish electrical suitability.
Manuals and model details
- Quantity and unit
- One current manual per exact product
- Specification
- Use exact model/revision, with conflicting instructions unresolved until manufacturer/installer clarification.
Prepare an enquiry
Uncertain information stays unknown. This checklist gives no safety score and sends nothing. After checking, copy only what you want to share with CAS. In the event of fire or immediate danger, move to safety and call 112. Do not wait for a reply to a form submission.
Worked example and formula
Task: extra socket. Room: study. Supply: unknown. Request an assessment; the list does not approve an installation.
Checklist only; no safety score or automatic submission
Formula version 2026-10-05.1
Sources
Would you like CAS to carry out the work?
Tell us about the room, equipment and changes you need. Agree the work, checks and warranty terms before the job starts.
First discuss whether CAS can take on your particular system and work.
Discuss the workIn the event of fire or immediate danger: move to safety and call 112. Do not wait for a form reply.