Introduction
The roof penetration for photovoltaic cables is one of the most critical tasks when installing a PV system. An incorrectly executed cable penetration leads to moisture ingress, current leakage, and in the worst case, fire hazards. This guide shows you how to safely and professionally route your PV cables through the roof – with the right materials and proven methods.
Why Professional Roof Penetration is Important
When routing solar cables through the roof, weaknesses in the building envelope are automatically created. A high-quality roof penetration with UV-stable TPU material protects against:
- Water ingress and moisture damage
- UV degradation: The material must last for 20 years
- Mechanical damage
- Electrical faults: Professional installation reduces fire risks
Step 1: Prepare Materials and Tools
Materials:
- NEXCAPE® roof penetration in the correct length (105mm, 125mm, or 150mm)
- DC cable (~7.5mm) or PE cable (~16mm diameter)
- Sealing tape or silicone
Step 2: Correctly Plan Drilling Position
Positioning is crucial: at least 30 cm from the roof ridge, not in the flow direction of rainwater, and easily accessible for future maintenance.
Step 3: Drill the Hole
Drill with the appropriate drill bit: 105mm → 60mm hole, 125mm → 80mm hole, 150mm → 100mm hole. Drill perpendicularly for a vertical roof penetration.
Step 4: Route Cable and Insert Roof Penetration
Route the cable from the inside through the roof penetration. Push the slider all the way – this activates the sealing lip. Seal with roof sealant.
Step 5: Seal and Secure
Seal the transition between the roof penetration and the roof membrane with suitable adhesive or bitumen. For flat roofs, we recommend additional sealing strips.
Size Advice: Which Roof Penetration Fits?
| Cable Type | Cable Diameter | Roof Penetration |
|---|---|---|
| DC Solar Cable | ~7.5 mm | 105mm NEXCAPE® |
| PE/Copper Cable | ~16 mm | 125mm NEXCAPE® |
| Multiple Cables | up to 18 mm | 150mm NEXCAPE® |
Conclusion
A professional PV cable roof penetration is not a cost center – it is an investment in the longevity of your system. With NEXCAPE® roof penetrations made of TPU, you have a product that lasts 20 years and is professional. Order roof penetrations now →
