Ethernet Cable – Flexibility of a UTP Cable

cableethernetlayer1power-over-ethernetutp

Is there a metric/specification that shows flexibility/elasticity of a utp cable? I have to install a utp cable and it will have to go around some sharp corners.

From what little experience I have with patch cables some seem to be more flexible than others. What should I pay attention to when choosing the cable?

Best Answer

Patch cables use stranded wire. This makes them more flexible, but performance is less than solid-core conductors.

Horizontal cables use solid-core wire, which makes them less flexible, but performance is better. These cables are not meant to be moved much after installation because repeated movement can break the solid wire.

The solid-core horizontal cable can be run for up to 90 meters, and the stranded patch cables on each end can total up to 10 meters.

UTP, in general, has an unloaded minimum bend radius of 4 times the cable diameter, which is about .25", so the minimum bend radius is about 1" with no tension.

There is also a maximum pulling tension when installing cables:

The maximum pulling tension for 4-pair, 24 AWG horizontal UTP cables should not exceed 110 N (25 lbf) to avoid stretching the conductors during installation.

Exceeding the bend radius or pulling tension can ruin a cable, and it will not pass the required test suite once it is installed.

ANSI/TIA/EIA maintains the standards for cabling, especially the ANSI/TIA/EIA 568 Commercial Building Telecommunications Cabling Standard and ANSI/TIA/EIA 569 Commercial Building Standard for Telecommunications Pathways and Spaces.

Unless you have the experience and proper tools, including a (very expensive) cable tester that can run the full test suite for the cable category which you are installing, you really are better off hiring a professional to do the installation.