Common Mistakes When Laying Solar Cables on the Roof
Laying solar cables on the roof is one of the work steps that determine the longevity of a PV system. Mistakes in cable routing lead to yield losses, safety risks, and expensive rectifications. Here are the most common mistakes – and how to avoid them.
Mistake 1: Laying cables freely on the roof
Exposed cables are subjected to UV radiation, weather, and marten bites. Even if the cable insulation is suitable for outdoor use, permanent exposure shortens its lifespan. Route cables through the roof into the protected roof space as quickly as possible.
Mistake 2: Too tight bending radii
Solar cables have a prescribed minimum bending radius. If this is not met, the insulation can be damaged – a creeping defect that only becomes a problem years later. Pay particular attention to sufficient space for the cable bend at the penetration point.
Mistake 3: Putting MC4 connectors under tension
If cables are laid too tightly, the MC4 connectors are subjected to mechanical stress. This can lead to contact problems and increased contact resistance. Always leave a cable loop as strain relief.
Mistake 4: Using unsuitable penetrations
Ventilation tiles, provisional drill holes, or silicone seals are not professional solutions for cable routing. They age quickly, become leaky, and look unprofessional. Rely on purpose-built roof penetrations such as NEXCAPE TPU penetrations – tool-free installation, sealed, and durable.
Mistake 5: Unnecessarily disconnecting MC4 connectors
Disconnecting and reconnecting MC4 connectors increases the risk of contact problems and arc formation. NEXCAPE penetrations are dimensioned so that MC4 connectors can be fully assembled and routed through – without disconnection.
Mistake 6: Forgetting or improperly routing earthing cables
Potential equalization is not an optional element. The earthing cable must be routed neatly and protected from the module array to the potential equalization point. The PE variants of NEXCAPE penetrations offer a separate opening for the earthing cable – all through one penetration point.
Checklist: Correct cable laying
- Plan cable routes before installation
- Use professional roof penetrations
- Adhere to minimum bending radii
- Provide strain relief at connectors
- Do not unnecessarily disconnect MC4 connectors
- Route earthing cables in accordance with standards
- Choose UV-resistant material (TPU instead of PVC)
Choosing the right penetration
NEXCAPE offers roof penetrations made of TPU, 3D-printed in Germany – for 2, 4, or 6 strings, with or without PE, in 105, 125, and 150 mm lengths. From 20 pieces with B2B volume discount.
Professional cable routing solution – find the right penetration now: find suitable PV roof penetration
