Comparison of Foiled and Non-Foiled Twisted-Wire Pairs Characteristics due to Coiling Stresses using the Feature Selective Validation Method

This paper compares the performance characteristics of foiled and non-foiled twisted wire pairs due to coiling stresses using the Feature Selective Validation Method (FSV) method. The use of twisted pair cables for Internet of Things (IOT) continues to grow due increasing demand for such applications. One of the ways devised by cable designers to minimize electromagnetic interference is the use of foils which comes with additional costs. However, in typical installations, cables could be subjected to repeated coiling and uncoiling stresses which can affect performance. There is limited knowledge in literature on the effects of foils on the performance of unshielded twisted pair (UTP) cables when subjected to coiling stresses anticipated during installation, hence the need to conduct this research. In this research, four UTP cables each of 30 meters' length, with two of them foiled were tested according to the International Standard ISO/IEC 11801 Class E which allows a maximum frequency of 250MHz for category 6 cables. The four UTP cables were subjected to three rounds of coiling and uncoiling tests to mimic handling stress expected in typical installations. The FSV method was used to assess the coiling stress effects on major performance parameters like return loss, near-end crosstalk (NEXT) and impedance of the four UTP cables allowed by the cable tester. The summary of the result of the assessment is that the two foiled cables gave the lowest variations between the first and fourth NEXT measurements for all the four pairs, while for return loss and impedance it is in two pairs. The approach presented can be used by cable installers and engineers to undertake an assessment of cables measurements selected for deployment.