Maximum tensile force of butterfly-shaped optical cable

Butterfly-shaped optical cables are designed with strength members to withstand tensile forces typically ranging from 600 N to 2700 N during installation, with standards defined by IEC 60794-1-311:2024 and DIN VDE V 0800-740.

Structural Design and Tensile Performance

Butterfly-shaped optical cables, commonly used in FTTH deployments, feature a flat profile with optical fibers at the center and parallel strength members on both sides. These strength members, often made of FRP (fiber-reinforced plastic) or steel wires, provide high tensile performance for both indoor pulling and aerial installations, while the flat geometry reduces bending stress and simplifies routing along walls and conduits (Hawell Cable) . The outer sheath, typically LSZH or PVC, enhances mechanical protection and fire safety.

Tensile Strength Standards

The tensile strength of optical cables is governed by international standards:

• IEC 60794-1-311:2024 specifies test procedures for tensile strength and elongation at break of optical cable elements, ensuring uniform mechanical performance across cable types .
• ITU-T L.103 (2024) emphasizes mechanical characteristics for indoor optical fiber cables, including tensile strength, bending, crush, and impact resistance, referencing IEC 60794 series for testing .
• DIN VDE V 0800-740 provides practical tensile force limits for installation, indicating that fiber optic cables can withstand 600 N to 2700 N during installation, depending on cable type, with operational tensile forces typically lower to prevent long-term damage .

Installation Considerations

During deployment, tensile forces must be carefully monitored to avoid microcracks or fiber breakage. Modern installation practices use digital force meters with ±2% accuracy and data logging to ensure compliance with tensile limits . The flat butterfly design helps prevent twisting and rolling, reducing stress on fibers and simplifying installation in tight spaces.

Summary

For butterfly-shaped optical cables:

• Installation tensile strength: 600–2700 N depending on cable type and installation method .
• Strength members: FRP or steel wires provide mechanical reinforcement .
• Standards compliance: IEC 60794-1-311:2024, ITU-T L.103, and DIN VDE V 0800-740 define testing and performance requirements .
• Operational safety: Tensile forces during normal operation should remain below installation limits to prevent long-term fiber degradation. These specifications ensure that butterfly-shaped optical cables maintain mechanical reliability, flexibility, and durability in FTTH and indoor/outdoor fiber deployments.