Material Selection for PV Roof Bushings: More Than Just Sealing
A roof bushing for photovoltaic cables must function reliably for decades – in heat, frost, UV radiation, and heavy rain. The material determines whether the bushing will still be sealed after 20 years or if it has long since become a weak point in the installation. For solar installers, knowledge of materials is therefore not a side issue, but business-critical.
Material Comparison
| Material | UV Resistance | Flexibility | Weight | Installation |
|---|---|---|---|---|
| Lead | Very Good | Easily Malleable | Heavy | Hammer Needed |
| EPDM | Good | Medium | Light | Easy |
| Aluminum | Good | Low | Medium | Tools Needed |
| TPU | Very Good | Very High | Light | Tool-Free |
Lead: Traditional, But Problematic
Lead bushings have been known in roofing for decades. They can be molded to tile profiles and are extremely durable. However, environmental aspects increasingly argue against the use of lead. In addition, the material is heavy and requires manual adaptation on the roof.
EPDM: Rubber with Limitations
EPDM (Ethylene Propylene Diene Monomer) sleeves are a widely used solution. They are lightweight and cost-effective. Disadvantage: EPDM can harden and lose elasticity with long-term UV exposure. For heavily profiled tiles, the adaptability is limited.
Aluminum: Stable, But Rigid
Aluminum bushings offer good corrosion resistance and are relatively lightweight. However, their rigidity makes them unsuitable for tiles with a pronounced profile. Gaps between the bushing and the tile must be additionally sealed.
TPU: The Best of Both Worlds
Thermoplastic Polyurethane (TPU) combines the advantages of the mentioned materials without their disadvantages. It is lightweight like EPDM, UV-resistant like lead, and highly flexible. TPU adapts to various tile profiles and maintains its elasticity throughout its entire lifespan.
- UV-resistant – no embrittlement over the years
- Temperature-resistant from minus 40 to plus 80 degrees Celsius
- Chemically resistant to environmental influences
- Lightweight and tool-free to install
NEXCAPE: TPU Bushings from the 3D Printer
NEXCAPE consistently relies on TPU as the material for PV roof bushings. Production takes place via 3D printing in Germany. The result: perfectly fitting, flexible bushings that are installed without tools. The PV cables are simply pushed through – no MC4 removal is necessary. Available in variants for 2, 4, and 6 PV cables, each optionally with PE bushing, and in three lengths (105, 125, 150 mm).
Discover TPU roof bushings in the shop: find suitable PV roof bushing
