7 basic rules for a good cable

Clear space is created in the centre of a cable depending on the number of cores and the cross section of each cable. This centre should be filled, as far as possible, with a proper core element (and not as frequently the case with fillers or dummy cores consisting of waste material). These measures will then efficiently protect the braided structure and prevent the cores from wandering into the middle of the cable.

Several test series have helped to determine which combination of wire diameter, pitch length and direction optimises bending resistance in cables optimised for movement. Although very flexible cables can be made using very thin individual wires, these tend towards extreme formation of kinks.

The insulation materials must be made so that they do not stick to one another within the cable. Furthermore, the insulation is required to support the individual wire strands of the conductor. Accordingly, only the highest-quality, high-pressure-extruded PVC or TPE materials that have proved their tested reliability in millions of core kilometres are then used in e-chain® applications.

The braided or layered structure must be formed around a strong, high tensile strength centre with an optimised short pitch length. However, due to the insulating materials being used, this stranded structure should still be defined in mobile form within the stranding. Starting from 12 cores, bundle stranding should be used.

A gusset-filling, extruded inner jacket is used instead of low-cost non-woven fabric, filler or tracer. This ensures that the stranded structure is efficiently held in the longitudinal direction. Moreover, the stranded structure cannot fall apart or move around. Hence, the inner jacket serves as solid foundation for the shield.

The shield should generally have a taut structure with an optimised angle of twist about an extruded inner jacket. Loose open braiding or wrapped stranding reduce the EMC protection considerably and can fail very quickly due to shield wire breakage. A tightly braided shield also has a torsion protection effect on the stranded structure.

An external jacket made of PVC, PUR or TPE can meet a wide range of specifications: from UV resistance through low-temperature flexibility and oil resistance to cost effectiveness. However, they should all have the following in common: a jacket material should be highly resistant to abrasion without sticking and highly flexible while still supportive. In addition, all external jackets should be extruded at high pressure (gusset-filling).