There was a period during the mid-1960's to about 1976, when aluminum was used in place of copper, for wiring residential homes. This came about because aluminum was lighter weight, cheaper, and more available at that time. However, aluminum wiring has since fallen out of favor, for a number of reasons. First, aluminum does not conduct electricity as well as copper wiring of the same size. This means it can't carry as many amps of current without heating up. Most importantly, aluminum wiring is more susceptible to connection problems: it expands and contracts to a greater degree, can corrode in the presence of moisture, and oxidizes quickly if exposed to air. Special terminals, connectors and anti-oxidant coatings are required to ensure a proper connection, and avoid potential hazard. For this reason, it's important to call a professional, anytime you need to repair or upgrade an aluminum system. To find out more about aluminum wiring, speak with a qualified electrician in your area.