A Comparison of Permanent Electrical Connections

The Bell System uses many types of electrical connections. The best connection for a specific application is chosen on the basis of the relative 1007 10C8 T H E BELL SYSTEM TECHNICAL JOURNAL, MAY 1964 merits of the connections in the following general areas: (1) adaptability of each connection for the application under consideration, (2) reliability or life required from the connections under the environmental conditions in which the equipment must operate, and (3) relative cost of each connection. This study was concerned with obtaining information on the comparative reliability or life of the four main types of permanent connections (solderless wrapped, soldered, percussive welded, and resistance welded) under various environmental conditions. The probability of the occurrence of substandard connections was recognized as a factor in determining the reliability of a given type of connection. However, only goodquality connections of each type were compared in this study, and all present manufacturing standards were followed in making them. All four types of connections are considered adequate for the applications in which they are presently used, and the results of this study should not be construed as a recommendation to change to a different type of connection in these applications. The scope of the program is illustrated by Fig. 1. It shows general wiring application (the connection of wires to terminals such as surface and local cable wiring) and the environments considered.