What is the inner jacket of a cable?

The structure of a cable is very complex, and like many other topics, it is not easy to explain in just a few sentences. Basically, the claim for any cable is that it operates reliably and efficiently for as long as possible. Today, we look at the inner jacket, or cable filler, which is an important part of managing the insides of a cable. To do this, we look at where the inner jacket is within a cable, what its purpose is, and how it can affect the service life of a cable.

Where is the inner jacket, and what does it do?

To explain the purpose of the inner jacket, we first have to take a closer look at where the inner jacket lies within the cable structure. Often, we find it in high quality cables that are designed for dynamic applications, and it is between the shield and the stranding.

The inner jacket separates the core stranding from the shielding. As a result, the wires are well guided while the inner jacket also serves as a secure foundation for the shield.

Inner jacket or banding with filler

As an alternative to an inner jacket—when there are less stressed lines—a film or fleece banding with filler can be used in its place. This design is significantly simpler and more cost-effective, particularly in the manufacturing of cables. However, an inner-sheath for cables that are moving within a cable carrier guarantees a significantly longer service life since the stranding element has much better support.

Inner jacket for long travels

The pressure-extruded inner sheath clearly demonstrates its advantages, particularly under high loads—like those that occur over long travels. When compared to an inner jacket, the disadvantage of a filler is that the filling element consists of soft textile materials which offer the veins little support. Additionally, the movement creates forces within the cable that can cause the wires to come loose from the stranding, which leads to a visible, screw-like deformation of the entire line. This is known as a “corkscrew”. This deformation can lead to wire breaks, and in the worst case, result in a plant shutdown.

Post time: Sep-12-2023