Connections made between conductors, in joining two ends together or in making a tap off the other, should be electrically and mechanical satisfactory which ensuing three fundamental criteria of safety, reliability, and cost effective to provide a path of electrical conduction between the conductors being joined. They not only should introduce no higher resistance (associated heating) at the points of contact, but they should also not be influenced of corrosion, conductor stress and movement.
For industrial and commercial applications, crimped and mechanically bolted aluminum and copper connectors are commonly used for terminating power cables. Copper connectors are available for use with copper conductor, and aluminum connectors are available for use with copper and aluminum conductor. There are significant differences in the material and electrical properties of aluminum and copper and their oxides, which may affect their long-term performance.
Parallel-groove clamps, split-bolt connectors, compression clamps and sleeves made more simple and more uniform, with substantial reduction in time and labor cost. Aluminum crimp connectors are also pre-filled with oxide inhibiting compound to reduce oxidation between the conductor and connector when in service.
Copper also oxidizes when exposed to air, but the oxide which forms is relatively soft and conductive, although not as conductive as the base metal. For this reason, copper connectors can often be installed without oxide inhibitor. Wire brushing of the conductor, although recommended, is not as critical as with aluminum. Copper connectors are often manufactured with a tin coating to reduce surface oxidation and discoloration, but they are also available without tin coating.