High transmission rates of up to 100 Mbit/s place high demands on the cable structure and its materials. The use of the cables in energy chains subjects these materials to additional stress and results in long-lasting alterations of the electrical properties. A CF 14.02.04.02.CAT5 cable was selected as a cable to be inspected for high transmission rates. Even when subjected to an application of stress with the minimum bending radius, the cable must also be able to meet the electrical requirements of the IEC 61156-6 standard. In the case of the CF14.02.04.02.CAT5 cable, four pairs of cores are stranded with one another, with each core pair possessing a nominal cross section of 0.25 mm2. The conductor consists of bare copper wires and is surrounded by an insulation sheath consisting of foamed PE.
Characteristic wave impedance of single pairs
Return loss of single pairs
Near-end crosstalk attenuation of single pairs versus one another
The test is to be carried out in order to determine whether the limit values of the IEC standard are complied with by the cable after being subjected to bending stress.
The maximum values of the individual attenuation for each pair of cores are specified for the corresponding nominal characteristic wave impedance in dB/100m in the DIN IEC 61156-6 standard. Accordingly, the cables are subdivided into several categories according to the transmission frequency planned to be used. For the cable being inspected, transmission frequencies of up to 100 MHz are planned to be used, which corresponds to the category 5e.
The attenuation, as a measure of the reduction of the transmitted electrical energy of a signal on the cable, remains, even after more than 1.5 million double strokes, below the specified limit value while being subjected to the application of stress of the minimum bending radius. The characteristic electrical transmission quantities such as characteristic wave impedance, return loss and near-end crosstalk are fulfilled so that, despite applications of high mechanical stress, the electrical values of the IEC standard are complied with for a cable of the category 5.
This test is, besides other things, basis of the Standard Warranty of up to 10 million cycles specified in the catalogue.