IEC TS 61586:2017 deals with the estimation of the inherent design reliability of electrical connectors through the definition and development of an appropriate accelerated testing programme. The basic intrinsic degradation mechanisms of connectors, which are those mechanisms which exist as a result of the materials and geometries chosen for the connector design, are reviewed to provide a context for the development of the desired test programme. While extrinsic degradation mechanisms may also significantly affect the performance of connectors, they vary widely by application and thus are not addressed in this document. This second edition cancels and replaces the first edition published in 1997. This edition constitutes a technical revision. The main technical changes with regard to the previous edition are as follows: A specific basic testing protocol is defined which utilizes a single test group subjecting connectors to multiple stresses, Additional information is provided concerning test acceleration factors, A discussion of the limitations of providing MTTF/MTBF estimates for connectors has been added and the bibliography has been expanded.