Influence of crimped connections in temperature rise tests

The resistance behavior of crimped connections in cables headed with crimped terminal lugs, used for rise temperature tests in the framework of the validation of electrical equipment, has been investigated. Analysis has been performed on test cables of two sections (240 mm2 and 185 mm2), available at the High Voltage and High Power Laboratory of the National Metrological Research Institute (INRIM). The resistance values showed a higher variability in larger section cables. The difference between the minimum and maximum value of the crimped resistance among the 240 mm2 cables was of about one order, going from 9.6 μΩ to 82.8 μΩ. The 185 mm2 cables, having better flexibility for their smaller section and less frequent use, and having been submitted to fewer tests, showed lower resistance variability with a variation between the maximum and minimum value of five times. The particular interest of the work is an analysis of the reliability of the crimping technique in the framework of the test activity, specifically relating to the validation of electrical devices such as circuitbreakers, switches, disconnectors, fuse-combination units and bus bar trunking systems.