Sufficient Load Capacity
It is important that your roof has enough load-bearing capacity to support the weight of a solar panel system. Keep in mind that the system's weight varies between 10 and 15 kg per square meter for a pitched roof and around 30 kg for a flat roof. On pitched roofs, the extra weight is usually not an issue. On flat roofs, it depends on the roof’s underlying structure. It's best to consult a structural engineer to determine whether your roof can support this additional weight.
Sufficient Space for the Inverter
Ensure there is enough space to install the inverter. It is often placed in the attic, basement, or garage. It's important to leave at least 30 cm of clearance around the inverter to allow heat to dissipate properly. This prevents the inverter from overheating.
Cable Routes and Empty Conduits
Installing empty conduits in advance is a smart way to prepare for solar panel wiring. This allows for a neat and concealed cable setup later on. We can also send pre-wired cables that you can install while the walls are still open, ensuring a clean finish. If you choose not to do this, we will do our best to conceal the cables neatly in cable ducts.
DC Cable
The solar panels are connected to the inverter using DC (direct current) cables. You can pre-install an empty conduit from the roof to the intended inverter location. This conduit should have a minimum diameter of 19 mm, but preferably 25 mm. For larger solar panel systems, multiple conduits may be necessary. If you're unsure, feel free to call us to discuss your specific situation. If you haven't decided on the inverter location yet, you cannot install the conduits yet, but you can start considering where the inverter should be placed—ideally as close as possible to the roof where the solar panels will be installed.
AC Cable
The AC (alternating current) cable carries power from the inverter to the electrical panel. It's advisable to pre-install an empty conduit between the inverter location and the electrical panel. Ensure that this conduit is sufficiently wide, ideally 25 mm. While most household AC cables have a cross-section of 2.5 mm2, we often use slightly thicker cables—4 mm2 or even 6 mm2— for the inverter. This is due to the inverter's power capacity and the length of the cables. A good installation should not have more than 1% power loss in the AC cables. Using cables with a 2.5 mm2 cross-section cannot always guarantee this.
Data Cable
To monitor your solar panels, an internet connection is required. Although the inverter can connect wirelessly via WiFi, this connection is often less stable. This is usually because the router is on the ground floor while the inverter is in the attic. We recommend connecting the inverter to the router via a wired connection. To prepare for this, install an empty conduit for the data cable. This should be at least 16 mm in diameter, but preferably 19 mm. The exact location depends on the placement of both the inverter and the router.
Preparations in the Electrical Panel
You can also make preparations in the electrical panel. The most important requirement is to reserve space for a residual-current circuit breaker with integrated overcurrent protection (RCBO). An RCBO is a combination of a residual-current device (RCD) and a circuit breaker, ensuring the solar panel system is electrically separated from the rest of the home. This prevents electrical issues with the solar panels from affecting other devices in the house. Note that the RCBO for solar panels is typically rated at 300 mA instead of the usual 30 mA. You can always check with us to determine the most suitable RCBO for your situation.
For a single-phase inverter, two slots are required in the electrical panel, while a three-phase inverter requires four slots. Ideally, these slots should be kept free on the sides of the distribution panel to allow for proper heat dissipation. If there is no space in the panel, we will install an additional surface-mounted box next to it.
Additionally, it is advisable to check which phase connection is needed for the solar panel system’s power capacity. In the Netherlands, a single-phase connection can accommodate an inverter with a power of up to 5000 watts, depending on the main connection size. A three-phase connection allows for higher power outputs.
Finally, it's wise to plan for future upgrades in your electrical panel. Starting in 2030, new gasoline-powered cars might no longer be sold in Holland, and more people will switch to electric vehicles. You can use the power from your solar panels to charge an electric car. You can reserve extra space in the panel for a future charging station connection. It is also advisable to install an empty conduit from the panel to facilitate the potential addition of a battery storage system for excess solar energy.
Roof Penetration
Installing a roof penetration for solar panel wiring is a useful preparation. A roof penetration is a pipe that runs through the roof and provides ventilation, exhaust, and cable routing. For pitched roofs, this is usually unnecessary, but for flat roofs, it is highly recommended. Retrofitting a roof penetration on a flat roof is more challenging. Position the roof penetration as far north as possible to minimize shading on the solar panel system.
Photos of the Roof Structure and Construction
If you are having your roof (re)built, it is advisable to take clear photos of the roof structure and construction. This helps solar panel installers prepare better for the installation, preventing unexpected issues later on.
