Introduction
The roof penetration of photovoltaic cables is one of the most critical tasks when installing a PV system. An incorrectly executed cable penetration can lead to moisture ingress, current leakage, and in the worst case, fire hazards. This guide shows you how to route your PV cables safely and professionally through the roof – with the right materials and proven methods.
Why professional roof penetration is important
Routing solar cables through the roof automatically creates weak points in the building envelope. A high-quality roof penetration with UV-stable TPU material protects against:
- Water ingress and moisture damage
- UV degradation: The material must withstand 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: Plan drilling position correctly
Positioning is crucial: At least 30 cm from the roof ridge, not in the direction of rainwater flow, 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 vertically 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 in so that the cable is routed neatly and without chafing. The roof penetration serves as mechanical abrasion protection at the tile edge; the rain-proof weather routing is handled by the professional roof covering (tiles and sarking membrane).
Step 5: Check and fix covering
Then cover the tile according to regulations and ensure a tension-free cable run. The weather-guiding function is ensured by the regular roof covering – the roof penetration itself is an abrasion protection. For flat roof or bitumen constructions, the connection is made according to the specifications of the respective roof system.
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 professionally manufactured. to TPU roof penetrations for solar cables
