Electrical Characteristics of Commercial Alloys

Electrical and other properties of copper render it the most widely used metallic conductor. Oxygen-free high-conductivity (OFHC) copper, having extremely low oxygen and other impurity contents, is produced for many electrical applications. Aluminum, having a conductivity only about one-half that of copper, is also frequently used as an electrical conductor. Silver has a higher conductivity than either copper or aluminum however, its use is restricted on the basis of cost. 

Copper is normally used for electrical wiring in residential and commercial buUdings. However, between 1965 and 1973, the price of copper increased significantly and, consequently, aluminum wiring was installed in many buildings constructed or remodeled during this period because aluminum was a less expensive electrical conductor. An inordinately high number 

When properly installed, aluminum wiring can be just as safe as copper. These safety problems arose at connection points between the aluminum and copper copper wiring was used for connection 

Warning signs that suggest possible connection problems include warm faceplates on switches or receptacles, the smell of burning plastic in the vicinity of outlets or switches, lights that flicker or burn out quickly, unusual static on radio/television, and circuit breakers that trip for no apparent reason. 

Two other less-desirable options are CO/ALR devices and pigtailing. A CO/ALR device is simply a switch or wall receptacle that is designed to be used with aluminum wiring. For pigtailing, a twist- 

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