A Comparison of Permanent Electrical Connections

Abstract

A study has been completed which compares four types of permanent electrical connections (soldered, solderless wrapped, percussive welded, and resistance welded) under environmental conditions of vibration, shock, temperature extremes, corrosion, humidity, and bending. Only good-quality connections were included in this study, and they represented the current state-of-the-art for each type. Under these conditions the connections showed no significant degradation in their electrical characteristics as long as they remained mechanically secure. Differences in the four types of connections were therefore assessed in relation to their mechanical characteristics. Consequently, one of the more important results of the study was the recognition of fatigue life as the most important mechanical connection characteristic when comparing connections which meet the high standards of the Bell System for electrical stability. Using fatigue life as a basis for comparison and soldered connections as a reference standard, the major conclusions with regard to general wiring (the connection of wires to terminals, such as surface and local cable wiring) are as follows for the conditions that existed in this study: (a) monitored percussive welded connections are superior to soldered connections; (b) over-all, solderless wrapped connections are essentially equivalent to soldered connections; (c) resistance welded connections are significantly inferior to soldered connections. Although differences were found among the types of connections, no evidence was obtained that any of the connection types are not satisfactory as presently used in normal Bell System applications.