Measuring Joint Resistances of Power Connections with Stranded Conductors – Fundamentals, Principles and Common Reasons for Measurement Errors

Abstract

Measuring the joint resistance of power connections with stranded conductors may be a challenging task. Generally, to apply four-terminal sensing is state of the art. Depending on the type of conductor and connection, the suitable type of current feed-in and potential tap has to be considered carefully. Especially tapping the potential correctly is one of the main issues for an accurate and repeatable measurement of joint resistance. The paper therefore summarizes the common methods to measure the joint resistance of power connections with stranded conductors. Further, it presents options for the electrical modeling of connections as well as conductors and compares the measurement methods theoretically. By the means of chosen examples, differences between the measured and the actual joint resistance are shown and discussed. Thereby, the influence of the coaction of conductor and connections as well as of the test setup is considered. The paper reviews these principle considerations in experiments on chosen power connections. This publication aims to reveal common errors in the joint resistance measurement and gives recommendations how to avoid them.