Roof renovation and PV system: Two projects, one plan
If a roof is being renovated anyway, it's the perfect opportunity to plan for a photovoltaic system at the same time. For solar installers, this means that the cable routing can be neatly integrated from the outset, instead of having to route it through existing structures afterwards. This saves time, material, and potential sealing problems.
Advantages of combined planning
- Integrate cable runs into the roof structure: No subsequent drilling or milling required
- Optimal positioning of penetrations: Determine placement directly during re-roofing
- Watertightness from day one: Penetrations are installed with the new roofing
- Cost advantage: Scaffolding and working time are only needed once
Planning steps for cable routing
1. System planning before renovation
Before the old tiles come off the roof, the PV system planning must be in place. String planning, inverter position, and cable routes determine where the penetrations will be placed.
2. Determine penetration positions
The roof penetration should be as close as possible to the transition between the module field and the inside of the roof. Short cable runs on the roof surface reduce UV exposure and the wind attack surface of the cables.
3. Calculate the number of penetrations
For each string, two PV cables (positive and negative) are usually routed through the roof. An earthing cable (PE) is added if required. NEXCAPE penetrations are available in variants for 2, 4, or 6 PV cables – each also with PE penetration.
4. Choose the length of the penetration
The penetration length depends on the roof structure: battens, counter-battens, and sarking membrane determine the distance between the tile and the inside of the roof. NEXCAPE offers three lengths: 105 mm, 125 mm, and 150 mm.
Installation during re-roofing
During a renovation, the penetration is installed directly when laying the new tiles. This is significantly easier than retrofitting, as the tile is not yet fixed and the substructure is freely accessible.
NEXCAPE roof penetrations made of TPU enable tool-free installation: simply push the cables through – the MC4 connector does not need to be removed. The flexible TPU material, manufactured by 3D printing in Germany, adapts to various tile profiles.
Common mistake: Cable routing as an afterthought
If PV cable routing is only planned after roof renovation, unnecessary additional costs arise. Tiles have to be lifted again, cable ducts subsequently drilled, and seals improvised. Better: Plan together from the start.
Order roof penetrations for new builds and renovations now: View PV roof penetrations
