The article presents the results of a study on the variation in contact resistance in connectors used in photovoltaic installations, depending on the number of disconnection and reconnection cycles. The analysis included MC4-type connectors supplied by various manufacturers recognized as leading market providers. The experiments were carried out in a controlled laboratory environment using a high-precision, voltage-based method capable of detecting very low resistance values. The connectors were disconnected 10, 50, and 100 times, and for each case, measurements were taken at three different nominal current levels. The results showed significant differences both in the initial resistance values and in the rate at which resistance increased with the number of cycles. The observed results vary strongly, indicating that manufacturing quality and the materials used in the connectors have a substantial impact on their long-term electrical reliability.
Rogowski et al. (Wed,) studied this question.